Ni47Ti44Nb9合金锻棒的织构及其对形状记忆性能的影响  

Texture and Its Effect on Shape Memory Properties of Ni47Ti44Nb9 Forged Rods

作　　者：孙明艳[1] 孟玉堂[1] 张永皞[1] 王英英[1] 范啟超[1] 黄姝珂[1] Sun Mingyan;Meng Yutang;Zhang Yonghao;Wang Yingying;Fan Qichao;Huang Shuke(Institute of Machinery Manufacturing Technology, China Academy of Engineering Physics, Mianyang 621900, China)

机构地区：[1]中国工程物理研究院机械制造工艺研究所

出　　处：《稀有金属》2018年第8期785-790,共6页Chinese Journal of Rare Metals

基　　金：四川省科技厅应用基础研究项目(2017JY0319);中国工程物理研究院科学技术发展基金项目(2015B0302060)资助

摘　　要：研究了Ni47Ti44Nb9合金锻棒的组织、织构、形状恢复率和可恢复应变，分析了锻造织构的形成机制以及对形状记忆性能的影响。采用扫描电子显微镜（SEM）观察了微观组织，采用X射线衍射（XRD）和背散射电子衍射（EBSD）分析了织构，采用小管扩径恢复法获得了形状恢复率和可恢复应变。研究结果表明，Ni47Ti44Nb9合金锻棒中的NiTi基体相沿轴向呈纤维状分布，纤维组织之间为β—Nb相，说明Ni47Ti44Nb9合金经过锻造变形后，NiTi相和β-Nb相都产生了较大的塑性变形。Ni477Ti44Nb9合金在锻造过程中主要形成了{111}〈110〉织构，即锻棒的轴向∥〈111〉方向、径向∥〈110〉方向。其形成机理可归结为Ni47Tk44Bb9合金在锻造过程中受到径向压应力的作用，使滑移面不断向垂直压应力轴方向转动，而滑移方向逐渐趋向于流变方向。Ni47Ti44Nb9合金在锻造过程中形成的{111}〈110〉织构使得在不同方向上进行扩径时获得的记忆性能存在差异，且当扩径方向∥〈110〉方向时比扩径方向∥〈111〉方向时获得的形状恢复率高3．52％，可恢复应变高0．62％．The microstructure, texture, recovery rate and recovery strain of the Ni47Ti44Nb9 forged rods were studied. The formation mechanism of texture and its effect on shape memory properties were also discussed. Microstructure were observed through scanning electronic microscope （SEM） , texture were analyzed by X-ray diffraction （XRD） and electron backscatter diffraction （EBSD） , recovery rate and recovery strain were tested by tube-expansion-recovery method. The results showed that NiTi matrix phase in the Ni47 Ti44 Nb9 forged rods distributed as fibers along the axial direction, while [3-Nb phase existed between the fibrous microstructures, which indicated that both NiTi and [3-Nb phases had large plastic deformation after forging of Ni47Ti44Nb9 alloy. The t 111 t 〈 1 10 〉 texture was mainly formed during the forging process of Ni47 Ti44 Nb9 alloy, that was, the axial direction of forging rod was parallel to the 〈 111 〉 direction while the radial direction was parallel to 〈 1 10 〉 direction. The formation mechanism could be attributed to the fact that during the forging process, Ni47 Ti44 Nb9 alloy was subjected to radial compressive stress, so that the slip surface continuously rotated to the direction perpendicular to compressive stress axis and the slip direction tended to the rheological direction gradually. In addition, I 111 } 〈 110 〉 texture formed in the forging process of Ni47Ti^Nb9 alloy could cause differences in shape memory properties when ex- panded in different directions. When the expanding direction paralleled to 〈 1 10 〉 direction, the recovery rate and recovery strain would be 3： 52% and 0.62% higher than the case of paralleling to 〈 111 〉 direction respectively.

关 键 词：形状记忆性能 Ni47Ti44Nb9合金 锻棒 织构 形状恢复率 可恢复应变 

分 类 号：TG139.6[一般工业技术—材料科学与工程]