冷变形MP35N合金的时效强化机理  

Strengthening mechanisms of cold worked MP35N alloy during aging treatment

作　　者：陈雨来[1] 杨东艳[1] 李静媛[2] 张源[2] 

机构地区：[1]北京科技大学冶金工程研究院,北京100083 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《哈尔滨工业大学学报》2017年第5期148-153,共6页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(U1660114);国家高技术研究发展计划(2015AA03A502)

摘　　要：为研究MP35N合金时效强化规律及机制,对MP35N合金进行84.18%的冷轧变形后,进行时效处理研究.在万能拉伸机上进行力学性能测试,用OM、SEM、TEM和EDS进行组织分析和微观成分测试.实验结果表明:在500℃时效4 h时,显微硬度达到最大值704.26 HV,抗拉强度为2641.16 MPa,与冷轧态相比,分别提高了30.44%和37.41%;该合金经时效后冷轧撕裂孔洞愈合,在400℃时效后出现了由34个厚度为3 nm左右的细小孪晶组成的"孪晶簇";温度升高到500℃,孪晶尺寸变大、交错,"孪晶簇"消失.未发现Mo原子在孪晶处处偏聚,时效过程中形成的纳米级片状孪晶起到主要的强化作用.The strengthening mechanism during aging treatment after 84. 18% cold rolling of MP35N alloy was performed in this study. Mechanical properties were tested on universal tensile testing machine and the microstructures were analyzed by OM,SEM,TEM and EDS. The results show that the maximum micro-hardness,704.26 HV,was obtained when MP35 N alloy was aged at 500 ℃ for 4 h,at which state the tensile strength was2641.16 MPa. The two values increased by 30. 44% and 37. 41% over cold rolling state respectively. Tear holes which formed during cold forming healed after aging and the TEM result revealed that the thin ＂twin cluster ＂consisting of 3 to 4 fine twins which thickness about 3 nm appeared after aged at 400 ℃. When the temperature increased to 500 ℃,twin size became larger,staggered and then ＂twin cluster＂disappeared. The EDS results shows there is no obvious concentration of Mo atom occurred in the twins. Nano flake twins formed during aging treatment play a major role in strengthening.

关 键 词：Co-Ni合金 冷轧 时效 强化机制 

分 类 号：TG135.1[一般工业技术—材料科学与工程]