高温长期时效对Hastelloy C-276合金组织和力学性能的影响

Effect of High-temperature Long-term Aging on Microstructure and Mechanical Properties of Hastelloy C-276 Alloy

对Hastelloy C-276合金在800℃进行了不同时间的时效处理,分析了其微观组织与力学性能的变化及高温拉伸的断裂机制。结果表明：Hastelloy C-276合金在800℃长期时效后的析出相为μ相和少量的M6C相。合金时效处理150 h后,晶界处开始有析出相产生;时效170 h后,晶界处出现连续的析出相并布满了整个晶界;时效310 h后,晶粒内部开始出现析出相,晶界处开始有少量析出相沿晶界向晶粒内部生长;时效510 h后,晶粒内部有大量的析出相出现;时效超过700 h后,晶粒内部的析出相开始聚集长大,几乎布满了整个晶粒。时效处理后的合金高温拉伸的断裂机制为微孔聚集型断裂。

The aging treatment（800℃ for different time） of Hastelloy C-276 alloy was carried out. The change of microstructure and mechanical properties and the high temperature tensile fracture mechanism were analyzed. The results show that the precipitated phases of Hastelloy C-276 alloy after long-term aging treatment at 800 ℃ are μ phase and a small amount of phase M6 C. After aging treatment for 150 h, the grain boundaries in Hastelloy C-276 alloy begin to produce precipitates; after aging treatment for 170 h, the grain boundaries are full of continuity precipitated phases; after aging treatment for 310 h, the interior in grain begins to precipitate, and a small amount of precipitates at the grain boundaries begins to grow along grain boundaries to the interior of the grain; after aging treatment for 510 h, a large number of precipitated phases arise in the grain interior; after aging treatment for above 710 h, the precipitates in the grain interior begin to aggregate and grow, which are almost full of the whole grain. The high temperature tensile fracture mechanism of the alloy is microvoid coalescence fracture.