A free-cutting and ductile CuAlMnZnTiB shape memory alloy

LIU Na(刘娜)^{1, 2}, LI Zhou(李周)^{1, 3}, LI Ling(李灵)¹, LIU Bin(刘斌)¹, LI Qing-tian(李擎天)¹, XU Gen-ying(徐根应)¹

(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education
(Central South University), Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)

Abstract:The mechanical properties and cutting performance of the designed CuAlMnZnTiB shape memory alloy were studied by tensile test and microstructure observation. Using X-ray diffractometry, differential scanning calorimetry (DSC) and semi-quantitative shape memory effect test, the microstructure and shape memory effect were analyzed. It is found that lots of β phase and few α phase are formed in the quenching of Cu-7.5Al-9.7Mn-3.4Zn-0.3Ti-0.14B (mass fraction, %) alloy, a great deal of martensite and few α phase are formed in the aging alloy, while the annealing alloy is composed of a great deal of α phase and few β phase. The tensile strength and elongation of the annealed alloy are 649 MPa and 17.1%, respectively. Some tiny and dispersion distributed second phase particles are generated in Ti and B precipitates, greatly improving the alloy machinability.

Key words:CuAlMnZnTiB shape memory alloy; mechanical properties; free-cutting