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In this study, typical microstructural characteristics of a metastable β Ti alloy (Ti–5Al–5Mo–5V–3Cr–1Fe) forged in a dual-phase region (strain of 54% at 820 °C) were investigated in detail by the combined use of X-ray diffraction, energy dispersive spectroscopy, electron channeling contrast imaging and electron backscatter diffraction techniques. Results show that the microstructure of the forged alloy is composed of bulk α grains, α plates and β matrix. The bulk α grains correspond to retained primary α phase (αp, average grain size ~ 2.4 μm), while the α plates are secondary α phase (αs, width ~ 70 nm) precipitated from the β matrix during air cooling. During forging, the β matrix experiences dynamic recovery with many subgrains and significant orientation gradients formed. Analyses of the orientation relationship between the α and β phases show that the Burgers orientation relationship is not maintained between some αp and β phases, which should be related to thermal deformation-induced changes of their orientations. In contrast, all of the αs plates are found to maintain well the Burgers orientation relationship with the β phase.

A sandwich structure of Mg alloy bulk consisted of two types of texture was fabricated by pre-twinning deformation. Its mechanical response and work hardening behavior during uniaxial compression were deeply analyzed to investigate the competition mechanism between basal slip and detwinning. Results showed that pre-twinning layer was a soft region. It undertook more than half of the strain by one third of the volume fraction of the bulk at the beginning of deformation. Slip behavior was significantly enhanced by detwinning and it took a more important role to coordinate local strain. Texture bonding promoted slip behavior in the grains exhibited “hard” orientations. Activation of detwinning behavior in pre-twinning region was mainly depended on basal slip behavior of their parents.

Corrosion behaviour of the low dielectric glass fibres in hydrochloric acid with different time and concentrations was studied. Leaching of cations, surface morphologies and structure of the low dielectric glass fibres before and after corrosion were investigated by ICP, SEM and FTIR, respectively. Both the change of weight and tensile strength of the low dielectric glass fibres in hydrochloric acid was discussed. The results showed that the decrease of weight and tensile strength of the low dielectric glass fibres with the increasing time was attributed to the leaching of the metal cations from the fibres surface which can disrupt the continuity of glass network. The equilibrium was eventually reached which was attributed to the formation of intermediate product, silica acid gel adhered to the fibres surface and complex of iron. The loss of weight and tensile strength had a maximum value after 8 h in 2 M hydrochloric acid and cracks were only generated on the surface after immersed in 2 M hydrochloric acid for 24 h. It suggested that the corrosion was significantly affected by the concentration of hydrochloric acid. The corrosion mechanism was not only attributed to ions exchange, but the hydrolysis of aluminoborate complex species.

The friction stir processed pure Ti was annealed at 550 °C with various annealing times. Dry sliding wear tests on friction stir processed and as-annealed pure Ti were performed at room temperature. Friction coefficient and wear rate of the alloys were measured. The results showed that the friction stir processed pure Ti with high hardness revealed lower wear resistance than as-annealed samples. The stored energy of the samples before and after annealing treatment were calculated. The relationship between work hardening and wear resistance of pure Ti was discussed. The run-in period increased as the stored energy in the pure Ti decreased. The fine-grained pure Ti with 400 kJ/m3 low angle grain boundaries stored energy exhibited the lowest wear rate. The wear mechanism of fine-grained pure Ti changed from fatigue wear and abrasive wear to adhesive wear after annealing treatment. Keywords: Titanium alloy, Friction stir processing, Annealing, Stored energy, Wear resistance

The microstructure and texture characteristics of commercial pure Ti after friction stir processing (FSP) with a slow rotation speed were studied. The shoulder friction zone (SFZ) which did not exist in the FSPed pure Ti with normal rotation speed (> 250 rpm) was observed in the sample treated with a slow rotation speed of 180 rpm. The texture of SFZ in the pure Ti was affected by shear stress from the shoulder of stir tool and the c-axes of the grains in this zone were nearly parallel to the processing direction. While crystallographic texture in the normal stir zone (SZ) were nearly perpendicular to the processing direction. The maximum depth of SFZ in the sample with 180 rpm was 1.2 mm, which decreased with the increased rotation speed until it disappeared. The grains in the SZ of specimen following FSP at a slow rotation speed were fine and homogeneous. The microhardness increased from 150.2 HV to 191.6 HV after FSP at 180 rpm. The microhardness trends were related to grain sizes, work hardening and texture evolution. The slow rotation speed processed alloy boosted the yield strength by 71.7% after the FSP.

Glasses with the composition 50SiO2-20TiO2-15BaO-7.5SrO-7.5CaO doped varied content of La2O3 have been prepared by the conventional melt quench technique. The effect of La2O3 on structure of the glasses was investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectra and Raman spectra. The density, thermal stability and dielectric properties of glass were measured and compared by the Archimedes method, differential thermal scanning analysis (DSC) and impedance spectroscopy, respectively. The results showed that the coordination of the titanium remained invariable with the addition of La2O3, while the number of Si-O-Ti bonds increased and the distribution of Qn changed. And the depolymerization of the glass network was observed. The thermal stability and resistance to crystallization increased significantly for glass containing 4 mol% of La2O3 resulting from the strong strength of La O bond and the La3+ clustering. However, the resistance to crystallization for glasses was decreased with further increasing La2O3. The dielectric constant of glass decreased first and then increased with the increase of La2O3 content, while the dielectric loss was almost constant.

A medium-strained (13% cold-drawing) 316L austenitic stainless steel rod was subjected to annealing between 750 and 1100 °C. Electron backscatter diffraction and electron channeling contrast imaging techniques were jointly employed to investigate the development of microstructures and grain boundary character distribution during the annealing treatments. Results show that annealing at temperatures below 900 °C does not evidently change microstructures of the as-drawn specimen. Full recrystallization is observed after the temperature reaches 1000 °C and the deformation microstructures are replaced by fine and uniform recrystallized grains. A large number of annealing twins (with Σ3 misorientation) are produced by the recrystallization, leading to markedly increased fractions of special boundaries (fSB). The maximum fSB is found to be 67.3% in the present study. In addition, for the recrystallized grains, rapid growth is noticed at relatively high temperatures due to easy migration of grain boundaries.

The structure and optical properties of CeO2/TiO2-doped boroalumnosilicate glass with the composition 54SiO2-10B2O3-13Al2O3-14Na2O-3ZnO-2Li2O-4CaF2 before and after gamma irradiation at varied dose were investigated by spectroscopy analysis. The results indicated that doping CeO2 and/or TiO2 can significantly improve structural stability against irradiation and that solely doping CeO2 or appropriate co-doping of CeO2/TiO2 achieves a perfect stabilization on optical property. A model based on self-repairing that irradiation may recover the structural defect via microstructure reconfiguration amid network depolymerization is employed to explain gamma irradiation-induced structural stability and stabilization of optical properties in presence of CeO2/TiO2.

An annealed Inconel 718 alloy was surface-treated by pulsed laser at three different powers (100, 50 and 25 W). Microstructural changes induced by the laser treatments were characterized by use of electron backscatter diffraction and electron channeling contrast imaging techniques. Results show that both annealing twins and strengthening precipitates profusely existing in the as-received specimen are dissolved at elevated temperatures during the laser irradiation. Meanwhile, in the melting zone (MZ), densities of low angle boundaries (LABs) are greatly increased with a large number of Laves phases preferentially distributed along such LABs. For different specimens, widths and depths of their MZs are found to be gradually reduced with decreasing the laser powers. Orientation analyses reveal that the columnar grains in the MZ of the 100 W specimen could inherit orientations existing in the matrix while lower laser powers promote the formation of more nuclei with scattered orientations to grow to be granular grains in the MZ. Hardness tests reveal that the MZs of all laser-treated specimens are softer than the matrix probably due to both precipitate dissolution and grain coarsening.

In this paper, electron backscatter diffraction and various other characterization and analysis techniques including X-ray diffraction, electron channeling contrast imaging and energy-dispersive spectrometry were jointly employed to investigate microstructural and textural changes of a hot-rolled Ti–6Al–4V (TC4) sheet after annealing at 800 °C for 5 h. In addition, the hardness variation induced by the annealing treatment is rationalized based on revealed microstructural and textural characteristics. Results show that the TC4 sheet presents a typical dual-phase (α + β) microstructure, with α-Ti as the major phase and short-rod-shaped β-Ti (minority) uniformly distributed throughout the α matrix. Most of α grains correspond to the un-recrystallized structures with a typical rolling texture (c//TD and //ND) and dense low angle boundaries (LABs). After the annealing, the stored energy in the as-received specimen is significantly reduced, along with greatly decreased LABs density. Also, the annealing allows recrystallization and grain growth to occur, leading to weakening of the initial texture. Furthermore, the water quenching immediately after the annealing triggers martensitic transformation, which makes the high-temperature β phases be transformed into submicron α plates. The hardness of the annealed specimen is 320.5 HV, lower than that (367.0 HV) of the as-received specimen, which could be attributed to reduced LABs, grain growth and weakened texture. Nevertheless, the hardening effect from the fine martensitic plates could help to suppress a drastic hardness drop.

Amorphous Si–C-based (a-SiC) thin films as protective coating have been attracting more and more attentions. But there are contradictory reports in the literature about the effect of sputtering power on the structural and mechanical properties of a-SiC films. Here, the influence of sputtering power on structural and mechanical properties of a-SiC thin films deposited by pulsed magnetron sputtering have been investigated. The results show that as-prepared films have a columnar structure and cauliflower-like pattern at lower sputtering power (100 W). Increasing the sputtering power from 100 W to 180 W, the columnar feature disappears and the thin films become denser. Meanwhile, the density of Si–C bond increases and the sp3/sp2 radio decreases. The hardness (H) and elastic modulus (E) of the a-SiC thin films increase when the sputtering power increases from 100 to 120 W and then their almost keep constant when the sputtering power increases from 120 to 140 W. Further increases in sputtering power, the H and E increase again. The maximum H and E are about 20.2 GPa and 223.1 GPa at 180 W, respectively. Reason for excellent mechanical property is proposed in combination with the theory analysis and experiment results.

Silicon containing diamond-like carbon films is of value for engineering applications operating at the temperature above 200 °C. This work presents a Si-gradually doped diamond-like carbon film with increasing the Si content from outer layer to inner layer deposited by plasma-assisted reactive magnetron sputtering process. The microstructure, chemical bonding state and temperature-dependence tribological properties upto 500 °C of the film are investigated by using focused ion beam/transmission electron microscope (FIB/TEM), X-ray photoelectron spectroscopy (XPS) techniques and ball-on-disk tribometer, respectively. The results show that the as-deposited Si-gradually doped DLC film exhibit amorphous structure. The wear track tested at 500 °C are composed of carbon, SiO2 and silicon oxide. High-temperature tribological tests show that the friction coefficient values are 0.05 ± 0.01, 0.02 ± 0.004 and 0.09 ± 0.04, while the wear rates are 1.17 × 10−7 mm3/N·m, 1.65 × 10−7 mm3/N·m and 1.4 × 10−6 mm3/N·m at 300 °C, 400 °C and 500 °C, respectively. It is proposed that the improved high-temperature tribological properties of the Si-gradually doped DLC film benefit from its special composition structure that the inner layer with high Si content provides the required mechanical properties and the outer layer with low Si content reduces the friction coefficient as well as the wear rate.

AA2099 Al-Cu-Li alloys were rolled by both asymmetrical and conventional rolling to a total thickness reduction of 80% at room temperature. Microstructure and texture evolution through thickness of rolling sheets were comprehensively investigated. Results show that large shear stress in ASR sample gave rise to a distortion of grain structure and a remarkable work hardening at region close to fast rolled surface. Shear banding behavior was largely promoted by ASR and various types of shear bands with higher density were observed. The shear bands triggered a kink of grain structure during rolling process. The kink behavior was related to the tilt angle and width of shear bands. The shear bands exhibited large tilt angle and width gave rise to a more significant kink of the grain structure nearby. Recrystallization during subsequent annealing was also promoted by ASR. Shear bands became favorable nucleation sites for rolled material. Growth advantage of some nuclei inside shear bands had a stronger influence on the recrystallized texture in AA2099 rolled sheets.

Hot compression deformation tests of AZ80 and AZ80-2 wt.% Sn magnesium alloys were performed on Gleeble-1500 at deformation temperature of 350 °C and strain rate of 0.1 s−1 to analyze the effect of Sn on the microstructure evolution. The results indicated that the addition of Sn promoted dynamic recrystallization and decreased flow stress during hot compression. Dynamic dissolution of discontinuous precipitation Mg17Al12 phases was promoted and dynamic precipitation of Mg17Al12 phases was suppressed in AZ80-2 wt.% Sn alloy. The quantity of Mg17Al12 phases of thermally compressed AZ80-2 wt.% Sn alloy was less than that of AZ80 alloy. Texture intensity increased in AZ80-2 wt.% Sn alloy during hot compression due to Mg17Al12 phases effectively induced particle-stimulated nucleation in recrystallization.

The aim of this work is to find how substrate bias affect the microstructure, mechanical, and tribological properties of the a-C/H films deposited on Ti6Al4V by magnetron sputtering. In order to attain this purpose, the structure of the deposited a-C/H film was investigated by scanning electron microscopy. Chemical bonding was examined by Raman spectroscopy techniques. Mechanical and tribological properties were evaluated using nanoindentation, scratch, internal stress, and ball-on-disk friction testing. The results showed that the sp2 content in a-C/H films increased as the bias voltage increased from − 400 to − 1200 V, indicating the graphitization of the films. The hardness (H) decreased from 29 to 18 GPa and the adhesion strength ranged from 13.1 to 25.3 N with increasing bias substrate. The average friction coefficient decreased at a bias voltage of − 300 V and increased when the bias voltage increased to − 1200 V. The best tribological performance was reached at − 600 V bias voltage. Reasons for the changing of structures, mechanical and tribological properties of a-C/H films were proposed.

The tribocorrosion behaviour of biomaterial Ti-25Nb-3Mo-3Zr-2Sn alloy in Ringer's solution was evaluated by micro-abrasion experiments, electrochemical tests and scanning electron microscope (SEM) observations. Potentiodynamic polarization results suggested that the effect of particle concentration on the electrochemistry characteristic is greater than the applied load. When the particle concentration and applied load were 0.05g·cm-3 and 0.25N, respectively, the Ecorr reached the maximum as -0.381V. The micro-abrasion-corrosion results showed that the wear rates of the Ti-25Nb-3Mo-3Zr-2Sn alloy increased with increasing particle concentration and decreased as applied load increased. The wear rates acquired under various conditions regarding to the main wear mechanism of two-body grooving wear with less three-body rolling wear; three-body abrasive wear modes are more efficient at material loss than two-body wear. The variation in material loss indicated that the contribution of corrosion is lower than the contribution of micro-abrasion. The wear regime, wastage and micro-abrasion-corrosion synergy maps associated with the particle concentration and applied load were established to evaluate the tribocorrosion behaviour of the Ti-25Nb-3Mo-3Zr-2Sn alloy as a potential surgical implant material.

Fluorine doped diamond-like carbon (F-DLC) coatings were deposited on Ti-6Al-4V alloy using a hollow cathode plasma immersion ion implantation deposition system. The aim of this work is to investigate the influence of F content on the surface morphology, structure, mechanical and tribological properties (under air and stroke-physiological saline solution) of the F-DLC coatings. The results reveal that the ratio of H/fE instead of H/E can be well predicting the anti-wear results when the F-DLC coatings have enough adhesion strength, where H is hardness, E is Young's modulus and f is friction coefficient. The F-DLC coatings with high F content exhibit excellent tribological property under air. The low F content F-DLC coatings present super-low friction coefficient and wear rate in stroke-physiological saline solution. Reasons for the tribological property are proposed in combination with the films' morphology and mechanical property.

Cylindrical specimens of as-extruded AA2099 Al-Li alloy are uniaxially compressed at temperatures ranging from 360 °C to 520 °C and strain rates ranging from 0.001 s−1 to 10 s−1. Processing map of these specimens was established. Electron backscatter diffraction (EBSD) measurements were performed for specimens deformed under various conditions to probe their microstructures and restoration mechanisms. Stored energies in various specimens are calculated based on statistics of low angle boundaries via EBSD data. The remarkable decrement of stored energy and misorientation characteristics reveal that dynamic recrystallization (DRX) happens at 480–520 °C and 0.001–0.1 s−1. Obvious DRX nucleation further suggests that this process should be classified to discontinuous dynamic recrystallization (DDRX). Stored energies in various specimens strongly affect the extents of dynamic recovery and dynamic recrystallization. By systemically considering the processing map and restoration behaviours of the specimens, the dynamic recrystallization regimes and the central high- η regimes are determined to correspond to preferable thermo-mechanical processing parameters for the as-extruded AA2099 Al-Li alloy.

The tribocorrosion behavior of the Ti-30Zr alloy as dental implant in Hank’s solution was evaluated. The results demonstrated that the wear volumes of the alloy increased as the applied load increase with/without electrochemical corrosion. The wear volumes acquired with corrosion exceeded the wear volumes without corrosion, whereas the difference between these two increased as the load increased. The material loss induced by the corrosion increased and the corrosion potential decreased as the loads increased, due to the interaction between wear and corrosion. The potentiodynamic polarization curves were acquired during wear. The corrosion potential (Ecorr) of −0.493 V was acquired at 1.0 N, while the Ecorr of −0.786 V was acquired at 5.0 N, indicating that the potential moved negatively as the applied loads increased, due to mechanical wear. Through observations of the 3-dimension surface and the SEM images of the worn surfaces, the visible scratches/grooves were observed along the sliding direction, indicating a predominant abrasive mechanism.

High-entropy alloy (HEA) coatings exhibit high hardness and high strength and have attracted wide attention. The improvement in the tribological performance, such as low friction coefficient and wear rate, is a longstanding challenge and is critical in the broad application of HEA coatings. In this study, a series of CrNbTiMoZr coatings was synthesized using the direct current magnetron sputtering by tuning substrate bias voltages. A continuous transformation in the structure from the amorphous phase to the face-centered cubic phase was observed in HEA carbide coatings. The residual stress and the hardness monotonously increased with the substrate bias voltage. The addition of carbon reduced the friction coefficient and the wear rate of HEA coatings. Consequently, we achieved a HEA carbide coating at −200 V combined with high hardness (17.4 GPa), low friction coefficient (0.3–0.4), and low wear rate (1.18 × 10−6 mm3·N−1·m−1). This study provides a new guidance for designing new HEA coatings with high strength and low wear.

CrNbSiTiZr high-entropy alloy films with different substrate bias voltages (from 0 V to–200 V) were fabricated on 304 stainless steel and Si substrates by radio-frequency magnetron sputtering. The microstructure, mechanical properties, tribological performance, and corrosion resistance were investigated in detail. Results show that all the as-fabricated films exhibit an amorphous phase. The columnar structure becomes featureless with the increase substrate bias due to re-sputtering effects and densification of the film. The film deposited at the bias of –50 V has a high residual compressive stress of –0.82 ± 0.04 GPa and a high hardness of 12.4 ± 0.3 GPa. The wear mechanism of the film is adhesive and slightly abrasive at low negative bias (0, –50, and –100 V), and that at high negative bias (–150 and –200 V) is abrasive. Polarization and electrochemical impedance spectrum measurements reveal that all films have a superior electrochemical corrosion resistance to the 304 stainless steel in 3.5 wt% NaCl solution, which indicates that the film can effectively protect substrate from corrosion. The values of Ecorr, icorr, and Rpo of the film deposited at the bias of –50 V are −283 mV, 0.0178 μA/cm2, and 2.084 × 106 Ω‧cm2, respectively.

Friction stir processing (FSP) was successfully performed on ultra-light dual-phase LZ91 Mg Li alloy, which provided a chance to study the microstructure and texture evolution of this alloy during severe plastic deformation. The results showed that LZ91 Mg Li alloy could be processed successfully with 200–400 rpm, 25 mm/min, and water cooling during FSP. No defects were observed on the surface and in the cross-section. The microstructure was strongly influenced by the material flow modes during FSP. Two greatly phase refinement regions were found in the stir zone where the α-Mg and β-Li phases were refined to submicron scale and homogeneously mixed. Maelstrom currents flow between two threads on the pin triggered this phase fragment. The high rotation rate of FSP leads to a remarkable recrystallization and grain growth due to the high heat input. The severe plastic deformation caused a phase transformation inside the refined α-Mg phase. The new phases enriched Li element exhibited a coherent relationship with the matrix. It shows that FSP promoted the short-term diffusion in refined α-Mg.

A rolled and recrystallized commercially pure Zr sheet was β-solution treated and then cooled at two rates, i.e. air cooling (AC) and furnace cooling (FC). Microstructures and textures of original and β-cooled specimens were characterized by use of electron channeling contrast imaging, electron backscatter diffraction and X-ray diffraction techniques. Results reveal a novel phenomenon, i.e. the concurrent inheritance of microstructure and texture in the FC specimen cooled at a very slow rate. In contrast, for the AC specimen with faster cooling, typical lamellar α phases are obtained with relatively scattered texture. Based on comparatively crystallographic and thermodynamic analyses, reasons accounting for microstructure and texture differences in both cases are discussed, highlighting the significant role played by the variant selection behavior. It is postulated that increasing cooling rates should be more feasible to change the transformed texture in Zr materials.

Two thermal-mechanical regimes were selected to investigate the recrystallization process of an as-extruded AA2099 alloy. Specimens were deformed to strains of 0.4, 0.7 and 0.9 at 520 °C and strain rates of 0.001 s −1 and 0.1 s −1 , respectively. Electron backscatter diffraction (EBSD) and electron channeling contrast (ECC) imaging were performed for all specimens to characterize their textures and microstructures. The texture evolution is reflected by variation of deviation angle between and extrusion directions, which appears to progressively approach ~35° ( //ED) due to lattice rotation in both regimes before e =0.7. The reconstruction maps indicate that the nucleation of recrystallization is related to strain incompatibility near grain boundaries. The textures of specimens deformed to strain of 0.9 exhibit significant difference between the two regimes, i.e the //ED fiber texture is comparatively weakened by recrystallization nuclei growth at the lower strain rate (0.001 s −1 ). ECC images for specimen deformed at 0.001 s −1 reveal significant differences in size and volume fraction of Al 3 Zr particles between recrystallized and unrecrystallized regions, suggesting remarkable influence of boundary migration on the thermal stability of Al 3 Zr particles.

In order to manifest the influence of specific microstructural component on the development of severe localized corrosion in an AA2099 aluminum–lithium alloy, the corrosion behavior of the alloy subjected to solution heat treatment, cold working and artificial ageing was investigated. Immersion testing and potentiodynamic polarization were employed to introduce localized corrosion; scanning electron microscopy and transmission electron microscopy were used to characterize the alloy microstructure and corrosion morphology. It was found that the susceptibility of the alloy to severe localized corrosion was sensitive to thermomechanical treatments. Additionally, the state of alloying elements influenced the mechanism of localized corrosion propagation. Specifically, the alloy in T8 conditions showed higher susceptibility to severe localized corrosion than that in other conditions. During potentiodynamic polarization, the alloy in solution heat-treated and T3 conditions displayed crystallographic corrosion morphology while the alloy in T6 and T8 conditions exhibited selective attack of grain interiors and grain boundaries in local regions.

Specimens cut from a rolled tin bronze sheet were annealed at 400–800 °C for 1 h and evolution of their microstructures was then characterized in details by electron channeling contrast imaging and electron backscatter diffraction techniques. Particularly, statistics on special boundaries (SBs) with Σ ≤ 29 and network connectivity of random high angle boundaries (HABs) in the annealed specimens were examined to probe optimization potentials of grain boundary character distribution (GBCD) for this material. Results show that the deformed microstructure in the as-received material begins to be recrystallized when the annealing temperature increase to 500 °C and average grain sizes surge with further increasing temperatures. As a result of the recrystallization, a large number of annealing twins (with Σ3 misorientation) are produced, leading to remarkably increased fractions of SBs (fSBs). Thanks to preexisting dense low angle boundaries, the majority of SBs in the 500 °C specimen with only partial recrystallization are Σ3ic (incoherent) boundaries, which effectively disrupt connectivity of random HABs network. Although the fSBs can be further increased (up to 72.5%) in specimens with full recrystallization (at higher temperatures), the Σ3ic boundaries would be replaced to some extent by Σ3c (coherent) boundaries which do not contribute directly to optimizing the GBCD. This work should be able to provide clear suggestions on applying the concept of grain boundary engineering to tin bronze alloys.

In this work, the surface of a fully recrystallized Zr702 is treated by pulsed laser following which microstructural changes are investigated by use of electron backscatter diffraction and electron channeling contrast imaging techniques. The pulsed laser treatment results in three distinctly different microstructural features from the surface to the substrate: fine α plates with a few hundred nanometers in width (zone I), irregular-shaped grains with varied sizes (zone II), and essentially unchanged equiaxed grains (zone III). The α plates result from rapid phase transformation due to easy heat extraction of the pulsed laser with dense nanoscale twins inside those plates closer to the surface. The origin of the irregular-shaped grains is found to be related to insufficient recrystallization of antecedently formed α plates near the substrate. Hardness tests reveal highest value (∼356.7 HV) near the surface in zone I and the lowest value (∼165.2 HV) in zone II. Reasons accounting for the difference are discussed in terms of various microstructural characteristics induced by the pulsed laser surface treatment.

The deposition parameters of high-entropy alloy films significantly influence their performance due to effective control of their microstructure. Thus, these parameters have become a research hotspot. In this study, CrNbTiMoZr high-entropy alloy films of amorphous or nanocrystalline solid solution were synthesized by direct current magnetron sputtering on silicon wafers and 304 stainless steel under different substrate bias voltages. The films' microstructure and tribo-mechanical properties were studied in detail. Results showed that the microstructure of films transformed from columnar structure to featureless with increased substrate bias voltage. In the nanoindentation test, the film deposited at −150 V exhibited the highest hardness of 9.7 GPa. Nevertheless, the CrNbTiMoZr films displayed excellent tribological properties under low bias voltage. Overall, our findings can guide the design of other novel high-entropy alloy films.

Peeling is considered to be the main technical obstacle for coating applications. There are many factors that affect the peeling process of coatings. The interfacial properties of the coating and substrate play a crucial role in the peeling process. In this study, the work of adhesion (Wad), interface energy (γi), and electronic structure of diamond (001)–Si(001) and Si(001)–Ti (0001) interface models have been investigated using first-principles calculations. The results indicate that the diamond (001)–Si(001) interface exhibits larger Wad and smaller γi values when compared with the Si(001)–Ti (0001) interface. However, the Wad of diamond–diamond, Si–Si, and Ti–Ti is 15.92, 4.92, and 3.84 J/m2, respectively. When compared with the two interface models, the Wad of Ti–Ti is the smallest, indicating that it will be the first to undergo deformation during the shear process. In addition, analysis of the charge density difference and density of states revealed that the interfacial Ti–Si bond is a covalent–metallic bond, which is much weaker than the Si–C bond (covalent bond), and therefore, the Si(001)–Ti (0001) structure is more inclined to delaminate.

The structure and corrosion resistance of anodized AA2099-T83 Al-Cu-Li alloy after layered double hydroxides (LDH) sealing and hot water sealing (HWS) were studied using scanning electron microscopy (SEM), X-ray diffraction, electrochemical impedance spectroscopy (EIS) and neutral salt spray test (NSST). Particularly, the corrosion resistance of the LDH-based coating system with reduced anodic film thicknesses was compared with that of the normal HWS-based coating system. It was found that LDH could be formed over the surface and within the pores of the anodic film within 30 min. With other conditions the same, the LDH-sealed alloy passed 1000 h of NSST without evident localized corrosion, contrasting with the HWS alloy, which showed severe localized corrosion after NSST for 120 h. Further, when the anodic film thickness was reduced from 3.7 to 1.3 μm, the LDH-sealed alloy still showed much better corrosion resistance than the normal HWS alloy. This work clearly demonstrates that it is possible to obtain high corrosion resistance for the anodized AA2099-T83 Al-Cu-Li alloy at much reduced anodic film thickness.

Diamond-like carbon films (DLC) with different silicon contents combined with W interlayer are deposited by plasma-assisted reactive magnetron sputtering. The structures and high-temperature tribological properties of the films are investigated. The results reveal that the pure DLC film is worn out at 400 °C because of graphitization, while the Si-DLC film with Si content of 4.56 at.% keeps low friction coefficient (0.2–0.05) at high temperature up to 500 °C. The 14.56 at.% Si-DLC film failed at 500 °C induced by the formation of SiO2. The improved high-temperature tribological performance of the 4.56 at.% Si-DLC film is attributed to the tribochemistry of W interlayer at 500 °C which formed a film composed of tungsten oxides and carbide.

The hot rolling microstructures and textures were strongly influenced by the prior heat treatments. Various prior heat treatments were utilized to investigate the effects of precipitates on microstructure and β-fiber texture after hot rolling. For the microstructure, the extent of planar slips strongly affects the hot rolling microstructure. Shear events of δ′ particles resulted in massive shear bands, which were the consequence of extensive planar slips. T1 platelets and T2 rods would homogenize the dislocation slips, resulting in a homogenous microstructure. The abnormal microstructure in overaged specimens was ascribed to successive work softening in the precipitation free zones (PFZs). With respect to hot rolling texture, the kind of precipitates in the matrix affected the intensities and locations of the β-fiber tube in Euler space, especially in the section between Copper and S orientation.

The micro-scale abrasive wear behavior of TiZrNbTa (TZNT) alloy in Hank’s solution and distilled water was studied using the TE66 machine. The effect of load and sliding distance was considered. The results of experiments show that the wear volume of the TZNT alloy is increased with increasing distance because of the greater damage, but the wear volume is not present the same regularity as the increase of load due to the effect of several factors. Only three-body abrasive wear is present at the lower load, while the mixed wear mechanism includes three-body and two-body abrasive wears at the higher load. Through observation, the wear appears under the same sliding distance at various simulated body fluids. The wear appearance is related to the wear mechanism. For wastage map, under the conditions of this paper, the majority of the area is medium wastage, the rest is low wastage, and there is no high wastage. The wastage map is related to the wear volume of the alloy under different conditions.

Localized corrosion in an AA2099-T83 aluminum–lithium alloy has been correlated with localized plastic deformation (LPD) introduced by cold working. The high population density of dislocations in the slip bands associated with LPD promoted preferential precipitation of needle-shaped T1 (Al2CuLi) phase during artificial aging. Consequently, preferential attack of the electrochemically active T1 phase in corrosive environment resulted in selective corrosion of the bands, leading to the development of the characteristic morphology of narrow, parallel volume of corrosion. Copyright © 2015 John Wiley & Sons, Ltd.

Fluorinated diamond-like carbon (DLC) films have good biocompatibility and bloodcompatibility. When they are used in cardiac valve prosthesis, the wear resistance has to be investigated in more detail. In this paper, the tribological behavior of fluorinated DLC films under different loads and sliding speeds in bull serum albumin (BSA) solutions were investigated by ball-on-disc friction tests. The results show that the proteins in BSA solutions promoted the DLC film adhesion failure because of the increased friction coefficients and accelerated corrosion rate. The fluorine doping can lower the corrosion rate of DLC film, thereby improving the adhesion stability and wear resistance of DLC in BSA solutions.

A Cu-10Fe alloy with magnetron sputtered Al films was irradiated by high current pulsed electron beam (HCPEB) with various pulse numbers, next changes of its microstructure and corrosion property were investigated. Compared with the initial sample, microhardness and corrosion resistance of the aluminized Cu-10Fe alloys after the HCPEB treatment are remarkably improved with increasing pulse numbers. This improvement could be attributed to formation of Al2Cu intermetallic compounds, occurrence of liquid phase separation and grain refinement in the surface layer of the Cu-10Fe alloy during the process of rapid remelting and solidification induced by the HCPEB treatment.

The erosion-corrosion behaviour of QSn6 alloy used as propellers in marine environment was evaluated by erosion-corrosion experiments with/without cathodic protection, electrochemical tests and scanning electron microscope (SEM) observations. The analysis was focused on the effect of flow velocity. The dynamic polarization curves showed that the corrosion rate of the QSn6 alloy increased as the flow velocity increased, due to the protective surface film removal at higher velocities. The lowest corrosion current densities of 1.26 × 10−4 A cm−2 was obtained at the flow velocity of 7 m s−1. Because of the higher particle kinetic energies at higher flow velocity, the mass loss rate of the QSn6 alloy increased as the flow velocity increased. The mass loss rate with cathodic protection was lower than that without cathodic protection under the same conditions. Also, the lowest mass loss rate of 0.7 g m−2 h−1 was acquired at the flow velocity of 7 m s−1 with cathodic protection. However, the increase rate of corrosion rate and mass loss were decreased with increasing the flow velocity. Through observation the SEM morphologies of the worn surfaces, the main wear mechanism was ploughing with/without cathodic protection. The removal rates of the QSn6 alloy increased as the flow velocity increased in both pure erosion and erosion-corrosion, whereas the erosion and corrosion intensified each other. At the flow velocity of 7 m s−1, the synergy rate (ΔW) exceeded by 5 times the erosion rate (Wwear). Through establishment and observation the erosion-corrosion mechanism map, the erosion-corrosion was the dominant regime in the study due to the contribution of erosion on the mass loss rate exceeded the corrosion contribution. The QSn6 alloy with cathodic protection is feasible as propellers, there are higher security at lower flow velocity, such as the flow velocity of 7 m s−1 in the paper.