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pISSN : 1598-706X / eISSN : 2288-8381


한국주조공학회지 (9권1호 58-66)

Study on the Effect of Crystal Morphology on Mechanical Property in Cu-Zn-Al Shape Memory Alloy

Cu-Zn-Al 형상기억합금에서 기계적 성질에 미치는 결정형상의 영향에 관한 연구;주조조직과 재결정처리에 따른 기계적 성질과 형상기억능의 변화

Sung-Jun Hwang, Jin-Hyung Lee*, Jong-Hwi Hong**

Korea University, *Kookmin University, **Korea University


The effect of heat treating temperature and α phase In the β phase matrix were investigated for β-CuZnAl shape memory alloys by tension test, fatigue test, and shape memory effect test. After heat treatment at 677℃, 750℃, 800℃ and 850℃ for 10 min. respectively, static fracture stress(∑_f), fatigue fracture stress(τ_{max}) at 10^6 cycle, and elongation(ε) was 24.2kg/mm^2, 17.21kg/mm^2 and 11.8%, respectively. As heat treating temperature decreased, fracture surfaces of the specimens were changed from the intergranular to the transgranular fracture mode. Especially, the a phase precipitated in the β phase matrix had an effect on crack propagation and the fracture surface was characterized by dimple-like pattern when crack propagated in transgranular cracking mode. Precipitation of the α phase in the β phase matrix lowered the transformation temperature by 10℃, and about 2.5 vol.% α phase did not affect the shape memory effect examined by the bending test.