Influence of quenchant variations solution treatment and holding time artificial aging on microstructure and hardness of Cu-Zn-Al alloys in shape memory alloy materials

Shape memory alloy is a smart alloy. One of these alloys is Cu-Zn-Al alloy. In this study, the Cu-11.9Zn-6.72Al alloy was used to analyze influence of variations in the cooling medium for the solution treatment process and variations in holding time for the artificial aging process of Cu-Zn-Al on the microstructure and hardness in shape memory alloy materials. Then the tests were carried out, namely OES, XRD, metallography and hardness. The microstructure of the solution treatment with variations in the cooling media of brine and ice water has a difference in the shape of the phase. The hardness of the solution treatment using brine cooling media has a greater hardness value than ice water cooling media with a value of 181.33±5.43 HV. The artificial aging microstructure with a holding time variation of 8 hours has twinned martensite which is darker than other holding time variations. The hardness of the artificial aging results increased from a holding time variation of 4 hours to 8 hours, with the highest hardness value of a holding time variation of 8 hours using ice water as a cooling medium of 248.67±10.65 HV.