增材制造技术在高温合金零部件成形中的应用

Application of Additive Manufacturing Technology in Forming of Superalloy Component

高温合金是指能够在600℃以上复杂应力状态下长期服役的金属材料,被广泛应用于航空航天以及核工业等领域。近年来,增材制造技术发展迅速,并且已经在高温合金零部件成形制造领域进行了大量应用探索。首先分别介绍了基于送粉和送丝的两种典型增材制造技术,以及利用以上两种技术成形得到的高温合金零部件微观组织形貌特征。由增材制造得到的高温合金零部件的微观组织以细长柱状晶为主,并且根据增材制造工艺的不同,微观组织中还会出现胞状晶和等轴晶;其次,由于增材制造技术具有快速冷却凝固的工艺特征,在一定程度上避免了宏观偏析现象的产生,但微观偏析等典型组织缺陷难以避免。需要经过后续热处理等工艺进一步消除,其中均质化+固溶+时效处理是最为常用且有效的热处理方法之一。最后,总结了增材制造技术在高温合金零部件成形中的特点,为进一步研究提供了建议和参考。

As a typical metallic material servicing under complicated stress state above 600℃,superalloy is widely used in aerospace,nuclear industry and other fields.In recent years,additive manufacturing technology has developed rapidly,and great progress has been made in the forming of superalloy components.Two typical additive manufacturing technologies based on powder feeding and wire feeding were introduced respectively.The microstructure characteristics of additive manufactured superalloy components were discussed.It was found that the microstructure of additive manufactured superalloy components was dominated by slender columnar grains.Moreover,cellular grains and equiaxed grains could appear under different additive manufacturing processes.Due to the rapid cooling and solidification process of additive manufacturing technology,the macro segregation was avoided to a certain extent.However,the micro segregation phenomena and some typical metallurgical defects were hardly prevented.For eliminating these defects,heat treatments and other processes,such as homogenization+solid solution+aging treatment,were commonly applied.Finally,the characteristics of additive manufacturing technology in the forming of superalloy components were summarized,providing suggestions and references for further research.