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用热重分析仪、X射线衍射仪、光学显微镜、示差扫描热分析仪和拉伸试验研究了Ti-50.8Ni形状记忆合金的组织、相变、形状记忆效应(SME)和超弹性(SE)特性。结果表明,Ti-50.8Ni合金在600℃以下退火后组织呈纤维状,在该温度以上退火后组织呈等轴状。加热温度超过600℃后合金氧化加剧。随退火温度Ta升高,合金冷却/加热过程中的相变类型由A→R→M/M→R→A型向A→R→M/M→A型再向A→R/R→A型转变(A—奥氏体,R—R相,M—马氏体),合金的M相变温度升高,R相变温度降低,M相变热滞降低,合金室温特性由SME+SE向SE转变。形变温度Td<20℃时,合金弹簧呈SME+SE,Td>30℃时,合金弹簧呈SE。随Td升高,合金弹簧的应力诱发M应力升高。
The microstructure, phase transformation, shape memory effect (SME) and superelasticity (SE) of Ti-50.8Ni shape memory alloy were studied by thermogravimetry, X-ray diffraction, optical microscope, differential scanning calorimeter and tensile test. characteristic. The results show that the microstructure of Ti-50.8Ni alloy annealed at 600 ℃ is fibrous, and the microstructure of the Ti-50.8Ni alloy annealed at this temperature is equiaxed. When the heating temperature exceeds 600 ℃, the oxidation of the alloy is aggravated. As the annealing temperature Ta increases, the type of phase transformation during the cooling / heating of the alloy changes from A → R → M / M → R → A to A → R → M / M → A to A → R / R → A Phase transformation (A-austenite, R-R phase, M-martensite). The phase transformation temperature of the alloy increases, the phase transition temperature decreases and the phase transition temperature decreases. Change to SE. Deformation temperature Td <20 ℃, the alloy was SME + SE, Td> 30 ℃, the alloy was SE. As Td increases, the stress of the alloy spring induces an increase in M stress.