Influence of heat treatment on mechanical properties and microstructure of the Al2024/SiC composite produced by multi–pass friction stir processing

• Published in: Measurement : journal of the International Measurement Confederation 2017-07, Vol.104, p.151-158
• Main Authors: Ghanbari, Davood, Kasiri Asgarani, Masoud, Amini, Kamran, Gharavi, Farhad
• Format: Article
• Language: English
• Subjects: Aging (artificial); Aluminum; Aluminum base alloys; Copper; Friction stir processing; Friction stir welding; Hardness; Heat treating; Heat treatment; Mechanical properties; Metal matrix composite; Metal matrix composites; Microhardness; Microstructure; Nanocomposites; Number of passes; Particulate composites; Precipitates; Wear; Wear mechanisms; Wear resistance
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2017.03.024

•Friction stir processing was fabricated AA2024/SiC by different passes number.•The effect of post heat treated on wear behaviour were analyzed.•By increasing number of passes, hardness of SZ decreased by increasing of S-phases.•Post heat treated increased the hardness due to dissolving the bigger S-phase.•The wear mechanism was the adhesive one in the composite and base metal samples. Aluminium matrix nano-composites were produced by friction stir processing of an Al-Cu alloy at different number of passes with pre-inserted SiC particles. The metal matrix composites were supplementary heat treated to elucidate the effect of heat treatment on microstructural changes and mechanical properties. The samples were fabricated by two and four passes. The supplementary heat treatment consisted of annealing at 590°C for 1h and artificial aging at 180°C for 8h. Microstructural studies showed that fine and co-axial grains along with uniform distribution nano-particles were formed in the stir zone (SZ). The agglomerated nano-scale particles were also observed in the samples. Micro-hardness results presented that in the SZ-region, hardness decreased with increasing the number of passes in the samples that were not heat treated. However, hardness uniformly increased about 70HV in the heat-treated samples. Wear mechanism in all of the samples was adhesive mechanism and the value of wear resistance increased about 170% in the heat-treated samples. The obtained results showed that the improvement of hardness and wear resistance in the heat-treated sample was related to the change in size and distribution of the S-phase precipitates in microstructure.