杨成功单际国温鹏任家烈
金属学报
doi:10.3724/SP.J.1037.2011.00167
采用Nd:YAG激光和光纤激光焊接了Ti-50.7%Ni(原子分数)记忆合金, 利用DSC, SEM和EDS对焊缝金属相变温度的变化规律和影响因素进行了分析, 并对焊接接头的记忆功能进行了研究. 结果表明, 不同焊接工艺参数的焊缝金属与母材相比,相变温度有明显差异, 产生差异的主要原因是组织的不同和基体Ni含量的差别. 基体Ni含量与C, O, N的含量、富Ni沉淀相尺寸和数量以及焊接过程中Ni的烧损有关.低热输入、高激光功率密度的焊缝金属, 基体Ni含量高, 相变温度偏离母材的程度更大.焊缝金属相变温度的变化使得焊接接头形状恢复温度区间明显不同于母材, 对其使用性能产生不利影响.
关键词:
激光焊接
,
shape memory alloy
,
transformation temperature
,
Ni content in the matrix
贺志荣
稀有金属材料与工程
采用拉伸和应力-应变循环实验研究了退火温度、时效温度、时效时间、形变温度和应力-应变循环对Ti-50.8Ni-0.5V(原子分数,%)形状记忆合金超弹性(SE)的影响.随退火温度的升高,合金的应力诱发马氏体临界应力(σM)先减小后增大,超弹性残留应变(εR)先增大后减小再增大,为了获得优异的室温SE,退火温度应取500~600℃.随时效温度的升高,合金的σM降低,εR增加,SE变差;随时效时间延长,300℃时效态合金的SE稳定,400和500℃时效态合金的SE变差.随形变温度的升高,σM增加,SE改善.随循环次数增加,400℃退火态合金的SE稳定;500℃退火态合金的σM降低;600℃退火态合金的SE由非线性向线性转变.
关键词:
Ti-Ni-V合金
,
形状记忆合金
,
超弹性
,
热处理
,
循环形变
Z.X Qinand Y.S. Zhang(Department of Materials Science and Engineering
,
Dalian Railway Institute
,
Dalian 116028
,
China)
金属学报(英文版)
The hyperfine interactions of two shape memory alloys have been studied by Mossbauer effect measurement at various temperatures. The Mossbauer spectra exhibit a mag-netic change from antiferro magnetic state to paramagnetic state when the temperuture rises. The Fe-Mn-Si alloys have a small hyperfine field and silicon element increases the hyperfine field and magnetic susceptibility. Thermo-induced γ→ ε trunsforma-tions are suppressed by Neel transition and by increasing carbon content, whereas stress induced γ→ ε transformation occurs in both alloys. Antiferromagnetic spin order can suppress thermo-induced γ→εtransformations efficiently, but cannot sup-press stress induced γ → ε transformation.
关键词:
phase transformation
,
null
,
null
,
null
C.L. Chu
,
G.J. Shen
,
S.D. Wang
,
B. Li
,
S.G. Zhang and Z.D. Yin(BOX 433
,
School of Materials Science and Engineering
,
Harbin Institute of Technology
,
Harbin 150001
,
China)(Analysis and Testing Center
,
Southeast University
,
Nanjing 210018
,
China)(Research Institute of Electric Light Source Materials
,
Ministry of Light Industry
,
Nanjing 210015
,
China)
金属学报(英文版)
From the orientation relationship between "Ti11Ni14" phase and matrix phase (B2),the accurate molecular formula of "Ti11N14" phase has been derived in this paper. The results also show that the rhombohedral unit cell of the "Ti11Ni14" phase includes six Ti atoms, seven Ni atoms and one vacancy, belonging to space group R3.
关键词:
TiNi
,
null
,
null