论文部分内容阅读
发现经不同热处理(固溶热处理及时效)工艺的近等原子Ni-Ti合金试样在冷却时会出现不同的相变顺序:除B_2(母相)→I(无公度相)→R相→M(马氏体相)及B_2→M外,在I相之前、R相之前或R→M之前,都会产生B2→M。提高固溶化温度使母相富Ni,从而使Ms~(B_2→M)及T_R下降,但形成等原子有利有序化。母相有序化使T_R升高,Ms~(R→M)下降。时效中发生有序化及沉淀两个过程。固溶化温度的提高,在700～750℃先使T_R上升,在750℃以上则下降。无公度相变也可能由原子面位移凝结所驱动。R相变有利于形状记忆效应,文中提出了可能的解释。R相对双程形状记忆效应约贡献1/3。
It is found that the near-atomic Ni-Ti alloy samples with different heat treatment (solution heat treatment and aging) process will have different phase transformation order when they are cooled: except B_2 (mother phase) → I (uncoordinated phase) → R phase → M (martensite phase) and B_2 → M, B2 → M occurs before phase I, before R phase or before R → M. Increasing the solid solution temperature makes the matrix rich in Ni, so that Ms ~ (B_2 → M) and T_R decrease, but the formation of isomorphous atoms is favorable. The parental ordering increased T_R and Ms ~ (R → M) decreased. Aging occurs in the ordering and precipitation of the two processes. Increasing the solid solution temperature increases T_R first at 700-750 ° C and then at 750 ° C or lower. Incommensurate phase transitions may also be driven by atomic-plane displacement condensation. R phase transition is beneficial to shape memory effect, the paper proposed a possible explanation. R relative to the two-way shape memory effect contributes about 1/3.