摘要
对MX246A合金进行了两段式均匀化热处理,采用扫描电镜观察了均匀化后的微观组织,测试了铸态和均匀化态MX246A合金在850℃和1100℃下的拉伸性能。结果表明,与铸态相比,均匀化热处理后MX246A合金的1100℃的塑性增加,但850℃的塑性降低。均匀化热处理后在枝晶间和晶界处存在大量被γ'包膜包覆的M6C碳化物;拉伸时,裂纹起源于这些碳化物,并沿碳化物与γ'包膜的界面进行扩展。在850℃时γ'包膜韧性差,碳化物处产生的应力集中无法释放是均匀化后MX246A合金的850℃塑性降低的主要原因。
Two-step homogenization treatment was conducted for MX246A alloy and the homogenized microstructure was observed by scanning electron microscope(SEM).The tensile properties of as-cast and homogenized MX246A alloy were tested at 850 ℃ and 1100 ℃.The results show that comparing with as-cast alloy,the ductility of homogenized MX246A alloy at 1100 ℃ is improved,but at 850 ℃ the ductility is reduced.A large amount of M6C carbides surrounded by γ' envelope precipitate is around interdendritic and grain boundary for homogenized MX246A alloy.During the tensile process,cracks can originate around the carbides and propagate along the carbide / γ' envelope interface.The poor toughness of γ' envelope and poor ductility of homogenized MX246A alloy at 850 ℃ are due to the stress concentration caused by the carbides can not be released.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2014年第4期162-165,共4页
Transactions of Materials and Heat Treatment
