论文部分内容阅读
为了研究不同状态的CuZnA(lRE)形状记忆合金在冷热循环过程中的热疲劳性能及记忆效应的变化,将铸态、水淬+时效和油淬+时效的三种CuZnA(lRE)形状记忆合金在电阻炉加热自约束热疲劳试验机上进行试验,并结合金相、X射线衍射和电子显微镜分析,研究不同循环次数下合金的裂纹和显微组织变化。结果表明:随着循环次数的增加,三种状态的CuZnA(lRE)形状记忆合金裂纹的长大速率随着循环次数的增加先增大后减小,铸态合金裂纹增长速率最快,裂纹最长,热疲劳抗力最低;水淬+时效的试样裂纹和热疲劳性能居中;油淬+时效的CuZnA(lRE)形状记忆合金,裂纹最短,热疲劳性能最高;随着循环次数的增加,马氏体内的位错密度增加,有序度下降,记忆效应衰减。
In order to study the thermal fatigue behavior and memory effect of CuZnA shape memory alloys with different states during hot and cold cycling, three CuZnA (lRE) shape memories, ie, as-cast, water quenched + aged and oil quenched + The alloys were tested in a resistance furnace heated self-restraining thermal fatigue tester. The microstructure, X-ray diffraction and electron microscopy were used to analyze the crack and microstructure changes of the alloys at different cycles. The results show that the crack growth rate of CuZnA (lRE) shape memory alloy increases with the increase of the number of cycles and then decreases with the increase of the number of cycles. The crack growth rate of the as-cast alloy is the fastest, Long, and the thermal fatigue resistance is the lowest; the crack and thermal fatigue properties of the sample quenched by water quenching + aging are medium; the CuZnA (lRE) shape memory alloy with oil quenching + aging has the shortest crack and the highest thermal fatigue property; as the number of cycles increases, The dislocation density in the body increases, the degree of order decreases, and the memory effect decays.