AerMet100钢有效晶粒细化与逆转变奥氏体稳定性的提高  

Refinement of effective grain and enhancement of reverted austenite stability for AerMet 100 steel

作　　者：梁锦奎[1] 王六定[1] 李志[2] 王佰民[3] 丁富才[1] 

机构地区：[1]西北工业大学理学院,陕西西安710129 [2]北京航空材料研究院,北京100095 [3]西北工业大学工程实践训练中心,陕西西安710129

出　　处：《材料热处理学报》2010年第5期57-60,共4页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金项目(50771082和60776822)

摘　　要：对二次硬化超高强度AerMet 100钢,通过引入预时效并优化双时效(即预时效+正常时效)工艺,膜状逆转变奥氏体(AR)中合金元素Ni、Co含量的起伏有利于提高其稳定性并降低Ms温度。高分辨透射电子显微镜(HRTEM)与扫描电子显微镜(SEM)分析表明:膜状AR在原奥氏体晶粒及马氏体铁素体(MF)板条边界形成,其间同时存在的K-S和N-W位向关系使有效晶粒由原奥氏体晶粒减小为MF板条(其厚度约80 nm);试样断面大而深的韧窝及高的撕裂棱反映出裂纹尖端钝化和分岔会吸收大量能量,在抗拉强度(σb)>2000 MPa条件下断裂韧度(KIC=127 MPa.m1/2)提高20%。By introducing the pre-aging and optimized double aging（pre-aging ＋ normal aging） technology for the secondary hardening ultrahigh strength steel AerMet 100,the fluctuation of density of Ni and Co,in the reverted austenite film shape（AR）,is beneficial to the reduction of martensitic starting transformation temperature（Ms） and the enhancement of AR stability.The analytic results of HRTEM and SEM show that AR forms as film shape at the boundary of the original austenite grains and martensitic ferrite（MF） lathes.Meanwhile the coexistence of K-S and N-W direction relationship between AR and MF reduces the effective grain size from the original austenite grain to the MF lath（about 80 nm） outstandingly.The large and deep dimples and long torn edges on the fracture surface suggest that the blunting and forking of crack tip can absorb significant amount of energy.In conclusion,on the condition that the ultimate tensile strength is more than（σb） 2000 MPa,the KIC（= 127 MPa.m1/2） is raised by 20%.

关 键 词：AerMet 100钢 逆转变奥氏体 有效晶粒 断裂韧度 稳定性 

分 类 号：TG142.24[一般工业技术—材料科学与工程] TG135.4[金属学及工艺—金属材料]