添加Ti对FeMnSiCrNi形状记忆合金性能的影响  

Effect of Ti addition on the property of FeMnSiCrNi shape memory alloy

作　　者：王志广[1] 李宁[1] 文玉华[1] 张伟[1] 

机构地区：[1]四川大学制造科学与工程学院,四川成都610065

出　　处：《金属热处理》2008年第3期13-16,共4页Heat Treatment of Metals

基　　金：国家自然科学基金项目(50501015)

摘　　要：研究了添加Ti对铁基形状记忆合金性能的影响。研究结果发现,添加Ti元素不仅使铁基形状记忆合金的力学性能得到改善,而且形状记忆效应也有较大幅度的提高。采用钨极氩弧焊(TIG)后,含Ti合金焊接后的抗拉强度达到706.9 MPa,是母材强度的98%,达到未加Ti合金母材的强度,远高于未加Ti合金焊接试样的强度(625.3 MPa)。添加Ti的铁基合金在800℃退火后,在4%弯曲变形下形状记忆效应达到92%,比未添加Ti合金在700℃退火处理后形状回复率高31%。SEM分析表明,添加Ti试样晶粒细小,而且在晶界观察到大量第二相粒子,因此焊接后未出现异常粗大的晶粒,焊接后表现为韧性断口。细晶强化和第二相强化是添加Ti合金提高形状记忆效应的主要原因。Effect of Ti addition on the property of Fe-based shape memory alloy （SMA） was studied. The result shows that the addition of Ti not only improves the mechanical properties of the Fe-based SMA, but also greatly enhances the shape memory effect. The tensile-strength of the Ti added specimen is 706.9 MPa after TIG welding, which is equal to the strength of the base metal without Ti addition, and is far higher than that of the welded specimen without Ti addition （ 625.3 MPa）. For the welding specimen, the tensile-strengthen of the alloy with Ti addition is larger than that of the alloy without Ti addition. The optimum shape memory ratio for the base metal with Ti addition reaches 92% after annealing at 800℃ for 30 min ,31% higher than that of alloy without Ti addition. Metallographic and SEM analysis shows that the grain of the alloy with Ti addition is finer than that of the alloy without Ti addition, and there is not abnormal coarse grain after TIG welding because some second-phase particles were precipitated on grain boundary. The welding specimen with Ti addition shows ductile rupture. The better shape memory effect of the alloy with Ti addition is obtained due to finegrain strengthening and second-phase strengthening.

关 键 词：铁基形状记忆合金 添加Ti 形状记忆效应 焊接性能 

分 类 号：TG139.6[一般工业技术—材料科学与工程]