中文摘要：

通过观察新型奥氏体耐热不锈钢（AFA不锈钢）试样在不同条件下再结晶的金相组织,研究了AFA不锈钢再结晶过程中的组织演变行为.结果表明,冷轧20%的AFA不锈钢试样在1473 K等温2 h以上才能完全再结晶;完全再结晶的试样在1023 K,应变速率为6.4×10-7s-1条件下拉伸时,稳态流变强度保持在130 MPa左右,并且具有良好的塑性变形能力和明显的加工硬化效果.但若不能完全再结晶,在相同实验条件下试样具有较高的强度（150 MPa）,但是塑性变差.AFA不锈钢再结晶晶粒长大过程受到NbC相析出的影响,其晶粒长大指数由理想晶粒长大的2变为3,表观激活能为234.7 kJ/mol,与Nb在奥氏体钢中沿晶界扩散的激活能吻合.

英文摘要：

Energy crisis and global warming demand development of high-performance structural materials to improve energy efficiency.For efficient energy conversion,the operating temperature and pressure of a heat engine used in boiler/steam turbine power plants should be as high as possible and materials used for the engine components must be able to withstand the high operating temperature.As such,next-generation structural materials simultaneously possessing higher creep strength and larger oxidation-resistance at elevated temperatures than those currently used are required.The conventional austenitic stainless steels,which rely on the formation of a tenacious Cr2O3 scale,would lose its protection capability at temperatures above 923 K,in particular in the presence of sulfur and water vapor.The alumina-forming austenitic（AFA） stainless steels are a relatively new class of dispersionstrengthened austenitic steels which showed superior oxidation-resistance to conventional stainless steels due to formation of the Al2O3-based protective scale at high temperatures.Recently,research focuses in this field have been mainly placed on high temperature oxidation-resistance,while little attention was paid to the mechanical property of these steels,particularly at elevated temperatures.In order to fully understand the deformation mechanisms at high temperatures,the recrystallization behavior in a typical AFA stainless steel under different conditions,including different annealing temperatures and durations,were investigated.The high-temperature mechanical properties of the AFA stainless steel samples heat-treated under different conditions were also studied.The sample was fully recrystallized upon heat treatment at 1473 K for at least 2 h and showed tensile strength about 130 MPa when tested at 1023 K with a strain rate 6.4×10-7s-1.The specimen was partially recrystallized upon heat treatment at1373 K for 0.5 h and exhibited a higher tensile strength of 150 MPa with decreased plasticity when tested under the same condition.Furth