热变形工艺对Incoloy800H合金微观组织的影响

Influence of hot working on microstructure of Incoloy800H

为提高Incoloy800H合金的质量,在Gleeble-3800热模拟试验机上,采用等温压缩的方法,研究了Incoloy800H合金的热变形行为。试验结果表明,在950～1 200℃,变形量为10%～60%,变形速率为1s-1试验条件范围内,合金具有良好的塑性,变形后试样表面质量良好;试样发生明显动态再结晶,温度越高,变形量越大,再结晶孕育期越短。该合金析出相多为TiC,TiN和Cr的碳化物,呈薄片状、菱形或不规则块状,尺寸大多在2～3μm。固溶处理后,基体析出大量的弥散细小的碳化物,在晶界处为薄片状,为裂纹易于产生与扩展的区域,对组织性能不利。

In order to improve the quality of Incoloy800H, the hot deformation behavior ot Incoloy800H is researched by adopting the isothermal compression method on the Gleeble-3800 hot simulation machine. The results show that Incoloy800H has an excellent plastic ability in the temperature range from 950-1 200 ℃ and deformation range from 10%-60% at the strain rate of 1 s-1 , and presents a smooth surface of specimens during the hot compressive deformation. The specimen has an obvious dynamic recrystallization, and with the increase of temperature and deformation rate, the incubation period oi the dynamic recrystallization is shortened. The precipitates in Incoloy800H alloy are mainly TiC, TiN, and an amount of precipitates contains chromium. The shapes of the precipitates are flake, lozenge and irregular block, and the sizes of them are about 2-3 um. After the solid solution treatment, a lot of tiny dispersions of carbide are generated in the matrix, while some flake carbides are generated near grain boundary region, which is not good to the mechanical properties of alloy because the flake precipitates are easy to produce grain boundary cracking.