A study on microstructural, mechanical properties, and optimization of wear behaviour of friction stir processed AZ31/TiC composites using response surface methodology.

The primary objective of this study is to investigate the microstructural, mechanical, and wear behaviour of AZ31/TiC surface composites fabricated through friction stir processing (FSP). TiC particles are reinforced onto the surface of AZ31 magnesium alloy to enhance its mechanical properties for demanding industrial applications. The FSP technique is employed to achieve a uniform dispersion of TiC particles and grain refinement in the surface composite. Microstructural characterization, mechanical testing (hardness and tensile strength), and wear behaviour evaluation under different operating conditions are performed. Response surface methodology (RSM) is utilized to optimize the wear rate by considering the effects of process parameters. The results reveal a significant improvement in hardness (41.3%) and tensile strength (39.1%) of the FSP-TiC composite compared to the base alloy, attributed to the refined grain structure (6-10 µm) and uniform distribution of TiC particles. The proposed regression model accurately predicts the wear rate, with a confirmation test validating an error percentage within ± 4%. Worn surface analysis elucidates the wear mechanisms, such as shallow grooves, delamination, and oxide layer formation, influenced by the applied load, sliding distance, and sliding velocity. The enhanced mechanical properties and wear resistance are attributed to the synergistic effects of grain refinement, particle-accelerated nucleation, the barrier effect of TiC particles, and improved interfacial bonding achieved through FSP. The optimized FSP-TiC composites exhibit potential for applications in industries demanding high strength, hardness, and wear resistance.

Mechanical property analysis and dry sand three-body abrasive wear behaviour of AZ31/ZrO2 composites produced by stir casting.

An experimental study of three body abrasive wear behaviour of AZ31/15 vol.% Zirconium dioxide (ZrO2) reinforced composites prepared by stir casting has been carried out. Microstructural analysis of the developed composites was carried out and found out that the microstructure of the composites revealed a uniform distribution of ZrO2 particles with refinement in the grain size of the matrix from 70 to 20 µm. The alterations in the microstructure led to an enhancement in both hardness (68-104 HV) and tensile strength (156-236 MPa) due to Orowan strengthening, quench hardening effect and better bonding. Response surface methodology was applied to formulate the three-body abrasive wear test characteristics such as load, speed, and time. Three body abrasive test results were utilized to generate surface graphs for different combinations of wear test parameters revealed an increase in specific wear rate. The specific wear rate was observed to increase with increase in speed up to a certain level and then started to decrease. The lowest possible specific wear rate was obtained for an optimized load of 20 N and a speed of 190 ms-1. Scanning electron microscopic examination of wear-tested samples showed higher specific wear rate at higher loads with predominantly abrasion type material removal. In conclusion, this study makes a substantial contribution to the field by elucidating the complex relationships among microstructure, mechanical properties, and the three-body abrasive wear behavior of AZ31/ZrO2 composites. The determination of optimal wear conditions and the insights gained into wear mechanisms provide valuable information for designing materials, implementing engineering solutions, and advancing the creation of wear-resistant components across a range of industries.

Microstructure, hardness and wear behavior of ZrC particle reinforced AZ31 surface composites synthesized via friction stir processing.

Dry sliding wear behaviour of friction stir processed (FSP) AZ31 and AZ31/ZrC particles (5, 10, and 15 vol%) reinforced surface composite was investigated at different sliding speeds and loads. The samples were tested using a pin-on-disc apparatus with EN31 steel as the counter body to determine the role of FSP and ZrC reinforcement on the microstructure, hardness, and wear behaviour of AZ31. Base metal AZ31 alloy exhibits a hardness of 60 HV, whereas the 15 vol% ZrC-reinforced composites had the highest hardness of 108 HV. It was also identified that 15 vol% ZrC-reinforced composites exhibited lowest wear rate and friction coefficient under all testing conditions. Abrasion, delamination, oxidation, material softening, and plastic deformation are the primary wear mechanisms viewed from the wear tracks of the samples. Higher volume fraction of ZrC particles exhibited better wear resistance at all speeds and loads than AZ31 alloy. A wear map has been generated for different material compositions and wear conditions to identify the main wear mechanisms easily.