采用电阻测量和X-射线衍射研究了Ti-54.91wt%Ni合金发生R相变的固溶和有序化处理条件。比较了不同残余应变量下经过 R 相变和只经过熟知的马氏体相变两种试样间的形状记忆特性。在近似等原子的 Ni-Ti 合金中 R 相变的发生取决于热处理...采用电阻测量和X-射线衍射研究了Ti-54.91wt%Ni合金发生R相变的固溶和有序化处理条件。比较了不同残余应变量下经过 R 相变和只经过熟知的马氏体相变两种试样间的形状记忆特性。在近似等原子的 Ni-Ti 合金中 R 相变的发生取决于热处理条件。除非在最有利的固溶和有序化组合条件下,通常并不存在 R 相变。延长有序化时间总是促进 R 相变。随着马氏体应变量的增大,不论是否附加 R 相变,形状回复温区加宽,单程形状回复率增高并出现极大值,而双程记忆效应单调地升高。在该合金中 R 相变的发生对于单程回复是有益的,但对于双程记忆则稍有削弱。形成 R相的热处理条件可以用声子形核的概念来解释。R 相变在单程和双程记忆上的不同效果可归因于加热(仅 M→B_2)和冷却(B_2→R 和 R→M)中经历不同的相变。展开更多
A new quenching-partitioning-tempering （Q-P-T） process was designed based on the recently developed quenching and partitioning （ ＆ P） treatment by Speer et al. The orientation relationships （ORs） of martensite...A new quenching-partitioning-tempering （Q-P-T） process was designed based on the recently developed quenching and partitioning （ ＆ P） treatment by Speer et al. The orientation relationships （ORs） of martensite （α） in Q-P-T steel tempered under different conditions were investigated using a scanning electron microscope with an electron backscatter diffraction unit. The morphology and crystallography of lath martensite within a packet were analyzed. Martensites exhibiting an initial austenite （y） grain in the orientation image map of different samples were chosen and their { 111 }α pole figures were drawn. The pole figures were fitted according to the ideal Kurdjumov-Sachs （K-S） and Nishiyama-Wasserman （N-W） ORs, which were calculated using Matlab and with a y crystal-oriented （001）γ[100]γ as the reference frame. The martensite OR in the Q-P-T steel follows both the K-S and N-W ORs; however, the K-S OR is predominant. This characteristic does not change in the samples further tempered at different temperatures.展开更多
文摘采用电阻测量和X-射线衍射研究了Ti-54.91wt%Ni合金发生R相变的固溶和有序化处理条件。比较了不同残余应变量下经过 R 相变和只经过熟知的马氏体相变两种试样间的形状记忆特性。在近似等原子的 Ni-Ti 合金中 R 相变的发生取决于热处理条件。除非在最有利的固溶和有序化组合条件下,通常并不存在 R 相变。延长有序化时间总是促进 R 相变。随着马氏体应变量的增大,不论是否附加 R 相变,形状回复温区加宽,单程形状回复率增高并出现极大值,而双程记忆效应单调地升高。在该合金中 R 相变的发生对于单程回复是有益的,但对于双程记忆则稍有削弱。形成 R相的热处理条件可以用声子形核的概念来解释。R 相变在单程和双程记忆上的不同效果可归因于加热(仅 M→B_2)和冷却(B_2→R 和 R→M)中经历不同的相变。
文摘A new quenching-partitioning-tempering （Q-P-T） process was designed based on the recently developed quenching and partitioning （ ＆ P） treatment by Speer et al. The orientation relationships （ORs） of martensite （α） in Q-P-T steel tempered under different conditions were investigated using a scanning electron microscope with an electron backscatter diffraction unit. The morphology and crystallography of lath martensite within a packet were analyzed. Martensites exhibiting an initial austenite （y） grain in the orientation image map of different samples were chosen and their { 111 }α pole figures were drawn. The pole figures were fitted according to the ideal Kurdjumov-Sachs （K-S） and Nishiyama-Wasserman （N-W） ORs, which were calculated using Matlab and with a y crystal-oriented （001）γ[100]γ as the reference frame. The martensite OR in the Q-P-T steel follows both the K-S and N-W ORs; however, the K-S OR is predominant. This characteristic does not change in the samples further tempered at different temperatures.
