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研究了钇对奥氏体耐热钢21Cr-11Ni-1.5Si-N的高温拉伸性能的影响及相关机制。在750~1 200℃,应变速率为0.005 s-1条件下进行了含与不含钇试样的热拉伸模拟试验及组织分析。结果表明:钇通过细化晶粒、强化晶界提高了试验钢在750~850℃的热塑性和抗拉强度;由于钇抑制了动态再结晶和再结晶晶粒长大,使得在850~1 050℃二者热塑性相当,而在1 050~1 200℃,含钇试验钢热塑性显著增加。另外,含钇试验钢经热加工后存有纤维组织;纤维状组织稳定性高,通过加热和动态再结晶也难以消除,而且其周围晶粒组织明显细小。
The effect of yttrium on the high temperature tensile properties of 21Cr-11Ni-1.5Si-N austenitic heat-resistant steel and the related mechanisms were studied. Thermal tensile simulation and microstructure analysis of the samples with and without yttrium were performed at 750-1 200 ℃ and strain rate of 0.005 s-1. The results show that the addition of yttrium can improve the thermoplasticity and tensile strength of the test steel at 750-850 ℃ by grain refinement and grain boundary strengthening. Because yttrium inhibits the dynamic recrystallization and recrystallization grain growth, ℃, the two are similar in their thermoplasticity, whereas the thermoplasticity of the yttrium-containing test steel is significantly increased at 1 050 ~ 1 200 ℃. In addition, the yttrium-containing test steel after thermal processing, there are fibrous tissue; fibrous tissue high stability, by heating and dynamic recrystallization is also difficult to eliminate, and the surrounding grain structure was significantly small.