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研究了添加Cr对形变退火态Ti-50.8Ni形状记忆合金氧化行为及组织和相变特性的影响。结果表明,添加微量Cr后,Ti-Ni合金的再结晶温度和抗氧化能力有所降低,相变热滞增加,相变温度大幅度降低。随退火温度升高,Ti-50.8Ni合金冷却/加热时的相变类型发生由A→R→M/M→R→A型向A→R→M/M→A型再向A→M/M→A型转变(A-母相,R-R相,M-马氏体),Ti-50.8Ni-0.3Cr的相变类型发生由A→R/R→A型向A→R→M/M→R→A型再向A→R→M/M→A型再向A→M/M→A型转变。随退火温度升高,二合金的R相变温度和M相变热滞降低,M相变温度升高,R相变热滞变化不大,保持在4℃左右。
The effect of Cr addition on the oxidation behavior and the microstructure and phase transition of Ti-50.8Ni shape memory alloy was studied. The results show that after addition of trace Cr, the recrystallization temperature and oxidation resistance of Ti-Ni alloy decrease, and the phase transition heat stagnation increases, and the transformation temperature decreases greatly. With the increase of annealing temperature, the type of phase transformation during cooling / heating of Ti-50.8Ni alloy occurs from A → R → M / M → R → A to A → R → M / M → A and then to A → M / The phase change types of Ti-50.8Ni-0.3Cr occur from A → R / R → A to A → R → M / M (A-parent phase, RR phase and M-martensite) → R → A and then A → R → M / M → A and then A → M / M → A. With the increase of annealing temperature, R phase transition temperature and M phase transition temperature of the two alloys decrease, M phase transition temperature increases, R phase transition hysteresis does not change much, and remains at about 4 ℃.