Thermal Effect of Quench Rate on Mechanical Properties of Sima 7075-T6

Abstract

In this study, thermal effects of quench rate on mechanical properties of 7075-T6 alloy fabricated by strain induced melt activation (SIMA) process were investi-gated. The T6 heat treatments were applied in various parameters after SIMA: solutionizing at 490 °C for 15-30-45-60-120 minutes, quenching at 60-100 °C, and aging at 120 °C for 12-24-48 hours. Optical and SEM analyses were per-formed for characterization, hardness, and tensile tests for mechanical evalua-tion. Analysis of variance tests was carried out to indicate the validity of the in-teractions quenching temperatures and tensile properties. Secondary phases were dissolved homogeneously after solutionizing but at higher quenching tempera-tures and re-precipitated, particularly at grain boundaries. Strength values de-creased with increasing quenching temperature. Analysis of variance tests sug-gest that cryogenic quenching can further increase the tensile properties. Oxide bifilms, porosities, low surface quality, and continuous brittle secondary phases surrounding spheroidal particles reduce the mechanical properties. © 2023 Society of Thermal Engineers of Serbia.