An Overview of Wear and How to Improve Wear Resistance

Wear is discussed in this study, as well as its impact on component performance and lifespan. It was mentioned how researchers are working to enhance the performance of materials. Due to enhanced hardness and finer grain structure, increased wear resistance has been recorded. Due to the particle strengthening process, it has also been observed that particle reinforcement improves wear resistance.

Fabrication and Characterization of Friction Stir-Processed Mg-Zn-Ca Biomaterials Strengthened with MgO Particles

Magnesium alloy composites play an important role in biomaterials field. In this study, a novel Mg-Zn-Ca matrix composite was reinforced by adding 1.0 wt.% MgO nanoparticles via the high shear casting process. Hereafter, friction stir processing (FSP) was used to achieve a good dispersion of MgO particles and improve the mechanical properties of the composites. After the preparation of the novel composite materials, varied characterization and performance test methods have been selected for comparison. The results illustrate that through FSP, the corresponding microstructure and properties of as-cast MgO/Mg-Zn-Ca composites were significantly modified, and the best combination of the key parameters is 1200 rpm and 60 mm/min for rotational velocity and traveling speed, respectively. After the optimized FSP treatment, the grains size in FSP-processed composites were refined by 42%, to reach 1.04 μm. Due to the grain refinement and the redistribution of MgO particles, the hardness of the FSP-processed MgO/Mg-Zn-Ca composites were increased by 40%, to reach 101.2 HV. Further, it displayed excellent corrosion resistance as well as strength. Compared to the strengthening through grain refinement, the particle strengthening is more dominant based on the study. And meanwhile, the modified grains and added MgO particles are beneficial to the properties of the nugget zones.

Effect of the Particle Size and Matrix Strength on Strengthening and Damage Process of the Particle Reinforced Metal Matrix Composites

Roles of the particle, strengthening, and weakening during deformation of the particle reinforced metal matrix composite, were studied using in situ technique. Composites with three different strengths Al-Cu-Mg alloy matrices reinforced by three sizes SiC particles were manufactured and subjected to in situ tensile testing. Based on in situ observation, damage process, fraction and size distribution of the cracked particles were collected to investigate the behavior of the particle during composite deformation. The presence of the particle strengthens the composite, while the particle cracking under high load weakens the composite. This strengthening to weakening transformation is controlled by the damage process of the particle and decided by the particle strength, size distribution, and the matrix flow behavior together. With a proper match of the particle and matrix, an effective strengthening can be obtained. Finally, the effective match range of the particle and the matrix was defined as a function of the particle size and the matrix strength.

Study on the Dissolution and Precipitation Behavior of Self-Designed (NbTi)C Nanoparticles Addition in 1045 Steel

Self-designed (NbTi)C nanoparticles were obtained by mechanical alloying, predispersed in Fe powder, and then added to 1045 steel to obtain modified cast steels. The microstructure of cast steels was investigated by an optical microscope, scanning electron microscope, X-ray diffraction, and a transmission electron microscope. The results showed that (NbTi)C particles can be added to steels and occur in the following forms: original ellipsoidal morphology nanoparticles with uniform dispersion in the matrix, cuboidal nanoparticles in the grain, and microparticles in the grain boundary. Calculations by Thermo-Calc software and solubility formula show that cuboidal (NbTi)C nanoparticles were precipitated in the grain, while the (NbTi)C microparticles were formed by eutectic transformation. The results of the tensile strength of steels show that the strength of modified steels increased and then declined with the increase in the addition amount. When the addition amount was 0.16 wt.%, the modified steel obtained the maximum tensile strength of 759.0 MPa, which is an increase of 52% compared with to that with no addition. The hardness of the modified steel increased with the addition of (NbTi)C nanoparticles. The performance increase was mainly related to grain refinement and the particle strengthening of (NbTi)C nanoparticles, and the performance degradation was related to the increase in eutectic (NbTi)C.

Effect of Nano-Al2O3 on Characteristics of Aluminium A356 Matrix Composite Produced by Stir Casting Route

Aluminium Matrix Composites (AMCs) made by A356 as matrix and nanoAl2O3 as reinforced are widely used for high performance application because of light weight and alumina has good performance at high temperature. In this study, the nanoAl2O3 used varied from 0.1 vf-% to 1.2 vf-%, which subsequently determined the optimum point. In addition, the magnesium with 10% are added as a wetting agent between aluminium and nanoAl2O3 as reinforced. Stir casting process is carried out for 2 minutes and 4 minutes for the degassing process using argon gasses then pouring molten metal in to the mold at 800°C. The effect of nanoAl2O3 on the mechanical properties and microstructure of the composites was investigated. The result showed that the tensile strength decreased with the addition of nanoAl2O3 but the hardness increased. Increasing of hardness mainly caused by grain refinement, and particle strengthening which act as obstacles to the motion of dislocations. Addition of nanoAl2O3 as reinforced also tend to form microporosity and agglomeration which would decrease the tensile strength of composites. The optimum strength was reached by 0.5 %Vf nanoAl2O3 with the value of 140 MPa and hardness of 46 BHN which was supported by low porosity level. Keyword : Al A356, Al2O3, nanoComposite, Stir Casting

Multi-strengthening-mechanisms in a novel titanium alloy with (TiHf)5Si3 particle-reinforcement

The microstructure and mechanical properties of Ti-2Si-2Nb-2Fe-1Hf-1Ta-1W alloy with (TiHf)5Si3 particle-reinforcement and their underlying relations have been studied. Electron microscope observations and correlative statistical analysis have been made to analyze microstructure evolution with heat treatments. The (TiHf)5Si3 particles with 800 nm in diameter were found uniformly distributed at α/β boundaries and triple junctions and turned out to be stable even after heat treatments at high temperature for a long period, inhibiting grain growth and dislocation motion. In addition, multi-strengthening-mechanisms including particle strengthening, solid-solution strengthening, grain boundary strengthening and dislocation strengthening have been discussed.

Effects of Ce-Rich Mischmetal on Microstructure Evolution and Mechanical Properties of 5182 Aluminum Alloy

This paper addresses the effects of Ce-rich mischmetal on the microstructure evolution of a 5182 aluminum alloy during annealing and rolling processes. The Ce-rich mischmetal was added to an as-cast 5182 aluminum alloy in an induction furnace, and this was followed by homogenized annealing at 450 °C for 24 h and a rolling operation. The microstructure evolution and mechanical properties’ analysis of the 5182 Al alloy were characterized. The results show that the Ce-rich mischmetal could modify the microstructure, refine the α-Al grains, break the network distribution of Mg2Si phases, and prevent Cr and Si atoms from diffusing into the Al6(Mn, Fe) phase in the as-cast 5182 Al alloys. Ce-rich mischmetal elements were also found to refine the Al6(Mn, Fe) phase after cold rolling. Then, the refined Al6(Mn, Fe) particles inhibited the growth of recrystallization grains to refine them from 10.01 to 7.18 μm after cold rolling. Consequently, the tensile strength of the cold-rolled 5182 Al alloy increased from 414.65 to 454.34 MPa through cell-size strengthening, dislocation density strengthening, and particle strengthening. The tensile strength of the recrystallization annealed 5182 Al alloy was increased from 322.16 to 342.73 MPa through grain refinement strengthening, and this alloy was more stable after the recrystallization annealing temperature.