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The effect of different annealing temperatures on the phase stability and mechanical properties of (FeNi)67Cr15Mn10Al5Ti3 high-entropy alloys (HEAs) was studied. The phase stability was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscattering diffraction (EBSD). The mechanical properties of the alloy were characterized by hardness and tensile tests. Furthermore, the heat-resistant corrosion properties of the (FeNi)67Cr15Mn10Al5Ti3 alloy after annealing at 800 °C was tested under high-temperature steam. The results indicated that HEAs exposed to different annealing temperatures always exhibited the face-centered cubic (FCC) phase. With rising annealing temperature, the dendrite structure of the alloys in the as-cast condition gradually disappeared, with recrystallization and precipitation of larger grains. The tensile strength of the alloy first increased and then decreased with the rising annealing temperature, the hardness and yield strength of the alloy decreased slightly, and the tensile elongation varied greatly. These findings can be used as a basis for improving the phase stability and mechanical properties of a Cr-Fe-Ni-Mn-HEA system with unequal atomic ratios. The heat and corrosion resistance of the alloy at 360 °C and 400 °C was better than that of Zr-4 alloy.

The effects of strain on the microstructure and mechanical properties of 0.81C-0.22Si-0.31Mn (wt%) high-carbon steel were investigated by thermal simulation, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), and an electron backscatter diffractometer (EBSD). It was found that when the steel was deformed at 670 °C (a temperature between A1 and Ar1), a deformation-induced pearlite transformation and cementite spheroidization occurred. The volume fraction of pearlite and the spheroidization ratio of cementite increased with a strain increase from 20% to 75%. The microstructure mainly consisted of pearlite when the deformation strain exceeded 40%. The aspect ratio was at its maximum (5.3) at 40% strain and decreased to 1.4 at 75% strain. In addition, the strength of the steel decreased and the elongation increased rapidly with the increase in strain from 20% to 60% due to the spheroidization of cementite. However, as the strain further increased to 75%, the strength increased slightly due to the refinement of the ferrite matrix. The comprehensive performance of the investigated steel can be improved by applying a strain between A1 and Ar1.

FeCrMnNi high-entropy alloys prepared by vacuum induction melting were tested and characterized using an X-ray diffractometer, a scanning electron microscope, a micro hardness tester and a universal tensile tester to investigate the effects of the heat treatment temperature on the microstructure and mechanical properties of the alloys and the heat-resistant corrosion properties of FeCrMnNi alloy after annealing at 800 °C. It is a high-entropy alloy with a typical dendritic (DR) morphology. With the increase in the heat-treatment temperature, the amount of ultrafine precipitates with the BCC structure in the matrix increased; furthermore, the amount of ultrafine precipitates started to decrease at temperatures above 900 °C, and the DR structure gradually weakened. After heat treatment at temperatures above 800 °C, the alloy showed a tensile strength of 721.1 MPa and an elongation at break of 26.7%, which indicates improved strength of the alloy while maintaining good plasticity, mainly because a large amount of nanoscale particles precipitated between the DR structures and enabled fine grain strengthening. Therefore, an appropriate heat-treatment temperature helps to improve the overall mechanical properties of the high-entropy alloy.

In this study, the flow behavior of a novel high entropy alloy, (FeNi)67Cr15Mn10Al5Ti3, was investigated through isothermal compression performed at temperature range of 980–1100 °C using strain rates of 0.01 s−1 and 0.1 s−1. The alloy was mainly composed of a face-centered cubic (FCC) phase and a small amount of body-centered cubic (BCC) phase. During deformation, the alloy exhibited typical single-peak type flow curve at all testing conditions. The stress exponent was determined to be ~5.5 with an apparent activation energy of ~426 kJ/mol, which indicated that dislocation creep was the rate-controlling process. Metallurgical inspection revealed that due to the plastic incompatibility of the two phases, the deformation is non-uniform especially at lower temperature and higher strain rate. Continuous dynamic recrystallization (CDRX) intensively occurred in both phases, but the recrystallization seemed to be much easier in the BCC phase. Dense low angle grain boundaries (LAGBs) were produced as a consequence of CDRX. At a lower strain rate, the LAGB ratio was evidently decreased with the increasing temperature. The sub-grain size was sensitive to the deformation parameter especially at a high temperature and low strain rate. A low temperature and high strain rate were beneficial for grain refinement but a much higher straining was required.

Interstitial free (IF) steel is widely used in the automotive industry, due to its excellent deep drawing performance. In this study, in order to study the influence of different rolling processes on the texture evolution and deep drawing performance of IF steel, we conducted rolling experiments on IF steel with different temperatures, different reduction rates, and different lubrication conditions. The impact of texture on the deep drawing performance of the steel was also analyzed. The microscopic and macroscopic texture analyses were performed using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD), respectively. Deep drawing performance was analyzed by measuring the r-value. The results showed that in non-lubricated rolling, the r-value increased with the decrease in the reduction rate, and the r-value increased with the increase in the deformation temperature. The maximum value of r is 0.85. But in the case of lubricated rolling, the r-value increased significantly from 0.74 to 1.47 compared to non-lubricated (keeping the reduction rate and the rolling temperature constant). The lubrication reduced the shear deformation of the steel surface, resulting in a γ texture on the surface. Texture uniformity along the thickness direction resulted in an increase in the r-value of the steel.

In order to investigate the influence of vanadium microalloying on deformation-induced pearlite transformation (DIPT) of eutectoid steel, thermomechanical simulation tests were carried out in this study. The following four compositions of vanadium microalloying were applied in the tests: vanadium free in Steel A, vanadium content of 0.1 mass% in Steel B, vanadium content of 0.27 mass% in Steel C, and vanadium content of 0.1 mass% with the addition of 0.02 mass% N in Steel D. The dissolution of vanadium and precipitation of vanadium carbides, nitrides, or carbonitrides and the effect of vanadium microalloying on the fraction and morphology of deformation-induced pearlite for different magnitudes of strain were examined, and the mechanism of the effect was elucidated. The results revealed that DIPT could be significantly improved by vanadium microalloying with the addition of N but decreased and postponed without the addition of N because vanadium nitrides or carbonitrides were precipitated in austenite under a small strain and facilitated the nucleation of pearlite both along the boundary of austenite grain (AG pearlite) and intragranular (IG pearlite). Moreover, transformation kinetics of DIPT was fitted and compared. The results further revealed that the rate of DIPT in vanadium-microalloyed steel with the addition of N was twice as fast as that in the vanadium-free steel. In order to ensure the complete spheroidization of lamellar cementites in vanadium-microalloyed steel, a comparison of the morphology of cementites revealed that a greater magnitude of strain was required.

Friction and wear seriously affect the safety use of winding hoist wire rope and the damage is a gradual process in practical application. In this paper, the tribological properties of a wire rope under different sliding distances were investigated. The evolutions of the coefficient of friction (COF), temperature rise, and wear characteristics under different contact loads and strokes were analyzed by a series of experiments. The results show that fluctuation of the friction is large in the early stages (before 10 min) and the major peaks depend on the stroke. When the contact load is 150 N, the COF increases most rapidly. It grows from approximately 0.48 to approximately 0.61 with the sliding distance. Additionally, the temperature rise in the wear region is higher under the large stroke (30 mm) and contact load (150 N). The maximum temperature rises are approximately 7.5 °C and 7.1 °C, respectively. Furthermore, it is approximately after 7200 mm that the temperature rise reaches a relatively stable stage. The wear scar region increases with the sliding distance and the maximum wear loss is approximately 65.5 mg at a load of 150 N. The major wear mechanisms of the wire rope are fatigue and adhesion wear.