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采用逐次添加的方式研究返回料循环使用次数(简称返回次数)对K465合金(返回料∶新料=1∶1)热疲劳性能的影响。研究发现:含返回料合金的热疲劳裂纹长度与热疲劳循环次数之间遵循L=b Na规律;氧含量是影响合金热疲劳性能的重要因素,在同等氧含量的情况下,合金的抗热疲劳性能随返回次数的增加而降低;含返回料合金的热疲劳裂纹的萌生、扩展与新料不同,其裂纹是在块状碳化物或疏松处萌生,并沿着枝晶间、晶界、开裂的碳化物及碳化物与基体的界面扩展。
The effects of the number of recycled materials (the number of times of return) on the thermal fatigue properties of K465 alloy (return material: new material = 1: 1) were studied by successive additions. The results show that L = b Na law follows the thermal fatigue crack length and the number of thermal fatigue cycles. The oxygen content is an important factor affecting the thermal fatigue performance of the alloy. Under the same oxygen content, the thermal resistance The fatigue performance decreases with the increase of the number of return cycles. The initiation and propagation of the thermal fatigue crack with the return alloy are different from those of the new material. The cracks are initiated at the massive carbides or loose areas, and along the interdendritic, Cracking of carbides and carbides and matrix interface expansion.