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Ti3AlC2 three-layered ceramics-reinforced copper matrix composites show not only the strength of the copper matrix but also better wear resistance, all while preserving its conductive property and, ultimately, reducing the cost of preparation. However, decomposition in Cu-Ti3AlC2 composites mainly occurs due to the severe interdiffusion of Al and Cu elements from Ti3AlC2 particle-grain boundaries, leading to the formation of TiCx. This work explored a practical method to produce Cu reinforced with a Ti3AlC2 particle which keeps an effective ternary layered structure by adding a nickel element. Results show that the addition of Ni elements results in a microstructure composed of Ti3AlC2, TiCx, NixAl, NixTi, and a Cu(Ni) matrix in the Cu-Ni-Ti3AlC2 composites. As the volume fraction of Ti3AlC2 particles increases, the morphologies change from a finely dispersed reinforcement phase to a continuous network, leading to a reduction in hole number and volume compared to Cu-Ti3AlC2 composites. This reduction is especially significant when the volume fraction of Ti3AlC2 exceeds 50%. The formation of NixAl and NixTi compounds at the grain boundary of the reinforcement phase after Ni element alloying restricts the diffusion of Al elements. The addition of Ni elements improves the mechanical properties of the composites. [ABSTRACT FROM AUTHOR]

To evaluate the enhanced erosion wear performance under acidic medium, a new high-vanadium–chromium alloy (HVCA) is designed and test samples produced by sand casting. The microstructure was analyzed by SEM, TEM and XRD. The erosion wear performance was tested in acidic medium designed by orthogonal test method. The factors affecting the erosion wear performance of HVCA are analyzed. The research results show that microstructure of HVCA is characterized by different carbides (M7C3, M23C6, VC, M2C) distributed in martensite and residual austenite. The hardness is 65.16 ± 0.2 HRC, and the impact toughness is 9.82 ± 0.12 J/cm2. H2SO4 concentration has the greatest influence on the erosion wear performance of HVCA, followed by the erosion wear angle. The maximum erosion wear performance of HVCA is 1.59 times that of HCCI. Compared with HCCI, HVCA has excellent erosion wear resistance because of its high hardness and toughness, a small amount of fracture and carbide shedding, and slight corrosion and wear interaction under erosion wear condition. [ABSTRACT FROM AUTHOR]

High chromium cast irons are commonly used as casting infiltration layers in the applications of wear resistance. The formation mechanism of the casting infiltration layer is essential to better develop the surface wear resistance materials using the casting infiltration method. In the present work, casting infiltration layers with various Cr contents were fabricated in situ on the surface of parent ZG45 steel. CALPHAD-type calculations using Thermo-Calc software, SEM, EDS and microhardness tests were performed to study the effect of Cr on the microstructure and hardness of casting infiltration layers. All the microstructures of casting infiltration layers were composed of pearlite matrix and eutectic M7C3 carbide. With the increase in Cr content from 7.01 wt.% to 17.20 wt.%, the amount of M7C3 carbide increased from 5.05 vol.% to 13.12 vol.%, resulting in the increment of microhardness. With the aid of simulations, the solidification behavior and formation mechanism of casting infiltration layers were revealed. [ABSTRACT FROM AUTHOR]

Yttria-stabilized zirconia particle–reinforced tungsten alloys were fabricated by using azeotropic distillation process coupled with powder metallurgy techniques. The influence of pH value of the original solution on the precursor powders' morphology and wear and mechanical properties of alloys was deeply studied. It showed that the precursor powder synthesized under solution with pH of 2 possesses finer particle size. The grain sizes of tungsten reinforced alloys obtained with different pH values vary from 2 to 6 μm, extremely smaller than that of pure tungsten. When pH value increases from 2 to 8, more and more bonding zirconia particles are obtained. The reinforced tungsten alloy prepared based on the solution of pH equal to 2 has better morphological and mechanical properties than the other two alloys prepared based on the solution of pH values of 5 and 8, respectively. The wear resistance of the reinforced tungsten alloy increases firstly and then decreases with the doping amount of zirconia particles. It is confirmed that the pH 2 value and chemical composition of the tungsten alloy with 3.0 wt. % Zr(Y)O2 exhibit the best wear resistance. The mechanical properties of the particle-reinforced tungsten alloy are improved with the decrease of pH value. The ultimate compressive strength and ultimate strain values of pH 2 reach to 1009 MPa and 0.23, respectively. The evolution of the relative density and associated porosity increases with the pH value. The abrasion mechanism was analyzed in detail. [ABSTRACT FROM AUTHOR]

In this work, the effect of Ce and Zr on the wear performance of a nickel-saving austenitic heat-resistant cast steel at room temperature and 900 °C are investigated. The wear mechanism and strengthening mechanism played by the addition of Ce and Zr are also discussed. The enhanced work-hardening rate after adding Ce and Zr strengthens the worn surface during wearing and improves the wear resistance of the nickel-saving austenitic steel at room temperature. The addition of Ce and Zr reduces the dynamic recovery and recrystallisation softening effect, which is the main reason for improving the high-temperature wear performance of the nickel-saving austenitic steel. Besides, the wear-protective glaze layer formed on the worn surface of Ce- and Zr-containing alloys could also reduce the high-temperature wear of the nickel-saving austenitic steel. [ABSTRACT FROM AUTHOR]

This study fabricates wear-resistant composite layers (WRCLs) strengthened with in situ vanadium carbide (VC) ceramics on the surface of carbon steel via casting infiltration technology. The abrasive and impact wear properties are evaluated accordingly. The action mechanism of VC ceramics of different scales in the wear process is clarified. The VC ceramics used in WRCLs include microscale primary VC and nanoscale secondary VC. Vanadium content exerts a considerable effect on the wear resistance of composite layers. The optimal vanadium contents for resisting abrasive and impact wear are 5.5 wt% and 5.1 wt%, respectively. The abrasive and impact wear resistance of the WRCLs are 2.5 and 1.9 times that of Cr20 cast iron as the vanadium content reaches the optimal amount. The improved wear resistance of the WRCLs is attributed to the synergy of the dual-scale VC ceramics. The microscale VC ceramics resist scratch efficiently while the nanoscale VC ceramics strengthen the matrix. Therefore, dual-scale VC ceramics work synergistically to reduce wear. [ABSTRACT FROM AUTHOR]

High-chromium cast iron with high nitrogen content (HNHCCI) was prepared using a vacuum induction barotropic furnace, and the erosion–wear behaviors of HNHCCI were investigated with a rotary erosion–wear tester. Results show that most of the nitrogen in HNHCCI dissolves into the matrix and some nitrogen forms carbonitride in the solidification process. The relative wear resistance of HNHCCI can reach 1.34 times that of high-chromium cast iron. The erosion–wear morphologies are ploughing, indentation, and large chips in water–sand slurry, whereas it is galvanic corrosion and carbide fracture in acid–sand slurry. HNHCCI has better mechanical properties and corrosion resistance than HCCI, decreasing the synergism of corrosion and wear. Therefore, HNHCCI has a lower erosion–wear rate. [ABSTRACT FROM AUTHOR]

• The wear resistance of high manganese steel is proportion to the worn subsurface hardness. • The worn subsurface hardness depends on the matrix hardness and wear hardening ability. • The hardness increment of worn subsurface was due to the formation of ε-martensite and twin. • The formation of mechanical nano-twins is promoted by stacking fault energy (SFE). • The ε-martensite content remains unchanged with the increase of SFE. To investigate the hardening mechanism of high manganese steel (HMS) during impact-abrasive wear (IAW), the microstructures and hardness evolution behaviours of the worn sub-surfaces of Mn13 (13.32% Mn and 0.22% Cr), Mn13-2 (13.23% Mn and 2.13% Cr), and Mn18-2 (18.35% Mn and 2.04% Cr) were investigated. The matrix hardness values of Mn13, Mn13-2, and Mn18-2 were 240.2, 256.6, and 266.5 HV, while their worn sub-surface hardness values were 670.1, 638.2, and 713.1 HV, respectively. The increase in the hardness values was attributed to the formation of ε-martensite and nano-sized mechanical twins in the worn sub-surfaces. The ε-martensite observed in the worn sub-surface of each of the three materials was similar. Therefore, the differences between the degrees of increase in the hardness values of the materials were attributed to the presence of the mechanical twins. The formation of the mechanical twins was affected by the stacking-fault energy (SFE), which increases with Mn content but decreases with Cr content. The degree of increase in the hardness increased in the following order: Mn13-2 (381.6 HV), Mn13 (429.9 HV), and Mn18-2 (446.6 HV). In summary, the degree of increase in the hardness of HMS during IAW can be improved by engineering a higher SFE for a higher number of mechanical twins. [ABSTRACT FROM AUTHOR]

High chromium cast irons (HCCIs) have excellent wear resistance because of high hardness chromium carbides (M 7 C 3). However, the hardness of M 7 C 3 is relatively low compared with MC-type carbides, such as VC, NbC and TiC. To improve wear resistance of HCCI, a new HCCI, named HCCI-VN, was fabricated by replacing wt.5.0% chromium with 5.0 wt% vanadium and adding 0.1 wt% nitrogen in traditional HCCI with 20 wt% Cr, and the abrasive wear properties of HCCI-VN were researched under different abrasive size and load conditions. Results show that the microstructure of HCCI-VN was characterized by many V(C, N) carbides besides chromium and molybdenum carbides (M 7 C 3 , M 23 C 6 , M 2 C), which were distributed in the matrix composed of martensite and austenite. The new HCCI-VN has excellent wear resistance. The relative wear resistance HCCI-VN is 2.2–9.1 times that of HCCI with 23 wt% Cr under different abrasive size and wear load. Among them, the reduction of abrasive size or the increase of wear load will bring better wear resistance. The excellent wear resistance of HCCI-VN is attributed to high hardness V(C, N), which cooperates with multi-scale and multi-type chromium and molybdenum carbides to resist abrasive scratch efficiently. • A new high chromium cast irons HCCI with vanadium and nitrogen (HCCI-VN) was fabricated. • The relative wear resistance HCCI-VN is 2.2–9.1 times that of HCCI. • The wear resistance mechanism of HCCI-VN is clarified. [ABSTRACT FROM AUTHOR]

Tungsten alloys reinforced by in-situ tetragonal zirconia (W–ZrO 2 ) were developed via the azeotropic distillation method combined with the powder metallurgy method. The microstructure and abrasive wear properties were studied. The in-situ ZrO 2 particles in the tungsten matrix were obtained by the decomposition of zirconium nitrate after liquid–liquid incorporation of (NH 4 ) 6 H 2 W 12 O 40 and Zr(NO 3 ) 4 aqueous solution. The ZrO 2 particles were distributed evenly in the tungsten matrix, which refined tungsten powders and the grains of tungsten alloys significantly. The density and Vickers hardness of the tungsten alloys decreased with increasing ZrO 2 mass fraction. However, the wear resistance increased firstly and then decreased with increasing ZrO 2 mass fraction. The optimal amount of ZrO 2 for improving wear property is 3%, with the wear resistance of W–3% ZrO 2 improving by approximately 20%–40% compared with that of pure tungsten. The proper amount of ZrO 2 particles can efficiently prevent microcutting to protect the tungsten matrix, thereby enhancing the wear resistance of tungsten alloys. [ABSTRACT FROM AUTHOR]

Abstract: This study developed a wear tester to investigate the wear properties of high-vanadium high-speed steel (HVHSS) with approximately 9% vanadium and different carbon contents under rolling–sliding condition. The carbon content significantly affected microstructure of matrix and mechanical properties of HVHSS, and therefore played an important role in wear resistance. Nevertheless, the wear failure mode was mainly related to sliding ratio, which varied from fatigue wear to sliding wear with increasing sliding ratio. The wear behavior was affected by the interaction of carbon content and sliding ratio. The high-stress rolling–sliding contact not only caused severe wear but transformed austenite to martensite. [Copyright &y& Elsevier]

The development of wear-resistant materials with excellent properties is of great research value in the manufacturing industry. In this paper, a new kind of low-vanadium wear-resistant alloy was designed and characterized to unveil the influence of vanadium content coupling with heat treatment on the microstructure, hardness, and abrasive wear property. The performances of commercial high chromium cast iron (HCCI) and the new low-vanadium wear-resistant alloy are compared. The alloy with 3 wt.% vanadium quenched at 900 °C and tempered at 250 °C, possessing VC, Mo2C, and M7C3 distributed in the martensite matrix, displayed a wear resistance two times better than the HCCI. The results showed that the increase of vanadium content from 0.98 wt.% to 3.00 wt.% resulted in a decrease in the size of M7C3 and a more homogeneous distribution of M7C3. VC with a bimodal distribution is effective for impeding grooving or indenting by abrasives because of their high hardness, which plays a vital role in improving the wear resistance of low-vanadium wear-resistant alloy. [ABSTRACT FROM AUTHOR]

Abstract: This paper is dedicated to the application of artificial neural networks in optimizing heat treatment technique of high-vanadium high-speed steel (HVHSS), including predictions of retained austenite content (A), hardness (H) and wear resistance (ε) according to quenching and tempering temperatures (T1, T2). Multilayer back-propagation (BP) networks are created and trained using comprehensive datasets tested by the authors. And very good performances of the neural networks are achieved. The prediction results show residual austenite content decreases with decreasing quenching temperature or increasing tempering temperature. The maximum value of relative wear resistance occurs at quenching of 1000–1050°C and tempering of 530–560°C, corresponding to the peak value of hardness and retained austenite content of about 20–40vol%. The prediction values have sufficiently mined the basic domain knowledge of heat treatment process of HVHSS. A convenient and powerful method of optimizing heat treatment technique has been provided by the authors. [Copyright &y& Elsevier]

The microstructure and abrasive wear performance of a novel wear-resistant steel designed based on the CALPHAD approach were characterized and evaluated. The steel exhibited distinct improvements over conventional high chromium cast iron through the precipitation of micron-sized M 7 C 3 carbides from austenite via desolation transformation, resulting in a more uniform distribution with smaller sizes and desirable shapes. Moreover, the steel incorporated micron-sized carbides (M 7 C 3 , VC, and Mo 2 C) and submicron carbides (M 7 C 3 and VC) as hard reinforcing phases, while nano-sized carbides (Mo 2 C, M 7 C 3 , and M 3 C) contributed to dispersion hardening. The wear resistance and impact-abrasive wear resistance of the steel were 1.8 times and 1.7 times superior to that of KmTBCr26 under identical wear conditions, respectively. These results indicated that the modified features of the micron-sized M 7 C 3 carbides effectively mitigated undesirable phenomena such as cracking and spalling during the wear process, leading to improved impact-abrasive wear resistance in this steel. The exceptional wear resistance was attributed to the synergistic effect of multiphase and multiscale carbides, demonstrating the effectiveness and potential of CALPHAD-inspired design strategies in developing advanced wear-resistant materials. • CALPHAD-inspired design strategies for developing wear-resistant materials. • Desirable M 7 C 3 carbides formed via desolation transformation. • Synergistic effect of multiphase and multiscale carbides on wear resistance. [ABSTRACT FROM AUTHOR]

Fe-Cr-C arc hardfacing deposits under air cooling (AC), water forced cooling (WC) and liquid nitrogen forced cooling (NC) were investigated. The fastest cooling rate and the lowest cooling finish temperature were obtained by WC and NC, respectively. Compared with AC and WC, NC led to the highest macro- and micro-hardness, and the most wear resistant. According to the three-body abrasive wear test results of dry sand/rubber wheel, the wear resistance of NC was 1.29 times that of AC. The cooling finish temperature (−125 ℃) of NC promoted the martensitic transformation. The martensite of NC was observed in the matrix of eutectic structure rather than in primary austenite (P-A), and showed a tetragonal structure, with lattice parameters a= 0.285 nm, c= 0.305 nm, because the high interstitial atom C in the lattice caused asymmetric lattice distortion. [Display omitted] • Water and liquid nitrogen cooling are used for hardfacing high chromium cast iron. • Circulating water forced cooling results in the fastest cooling rate. • The cooling finish temperature of liquid nitrogen is as low as − 125 ℃. • Liquid nitrogen cooling improves the wear resistance of deposits significantly. [ABSTRACT FROM AUTHOR]

Liquid nitrogen jet cooling was used to improve the microstructure and wear-resistance hardfacing high chromium cast iron. [Display omitted] • Three arc surfacing layers of high chromium cast iron were prepared. • Air and liquid nitrogen cooling were used. • Liquid nitrogen cooling made primary austenite fine, equiaxed and evenly distributed. • Liquid nitrogen cooling improved the wear resistance. • Abrasive particles could penetrate primary austenite and cut effectively caused the most severe wear. The influences of cooling conditions on the microstructure and abrasive wear behavior of arc surfacing layer of high chromium cast iron (HCCI) were investigated. The surfacing alloys were prepared by air and liquid nitrogen cooling. Microstructure of the alloys was studied by optical microscopy and scanning electronic microscopy, and the wear behavior was researched using pin-on-disk test. The primary austenite (P-A) was refined and its morphology was improved significantly by liquid nitrogen jet cooling. The wear resistance test indicated that under the same conditions, the liquid nitrogen jet cooling hardfacing alloy showed better wear resistance. According to analyzing the worn surfaces, the size of P-A and abrasive particles, the wear mechanism was revealed. Specifically, as the weak structure of surfacing alloy, P-A was easily penetrated by SiC particles. When the abrasive particles own the penetrable size as well as the cutting ability to P-A, the wear of surfacing alloy is intensified. [ABSTRACT FROM AUTHOR]