预变形对DT740高密度合金组织和力学性能的影响  

Effect of pre-deformation on microstructure and mechanical properties of DT740 high density alloy

作　　者：张胜 王春旭[2] 姜庆伟[1] 刘少尊[2] 李建新 厉勇[2] Zhang Sheng;Wang Chunxu;Jiang Qingwei;Liu Shaozun;Li Jianxin;Li Yong(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming Yunnan 650093,China;Institute of Special Steels,Central Iron and Steel Research Institute,Beijing 100081,China;Technology Center,Fushun Special Steel Co.,Ltd.,Fushun Liaoning 113000,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081 [3]抚顺特殊钢股份有限公司技术中心,辽宁抚顺113000

出　　处：《金属热处理》2019年第12期101-106,共6页Heat Treatment of Metals

基　　金：国家重点研发计划(2016YFB0300104)

摘　　要：采用洛氏硬度计、室温拉伸试验机、扫描电镜、透射电镜和X射线衍射仪等试验方法,系统研究了不同预变形量下DT740高密度合金的力学性能及显微组织的变化规律。结果表明:随着预变形量的增加,DT740合金的强度和硬度逐渐增加;当预变形量为35%时,合金具有最佳的强塑性配合,且拉伸断裂方式为微孔聚集型断裂。预变形促进了DT740合金时效过程中Ni4W相的析出,随着预变形量的提高,Ni4W析出相的数量和位错密度均不断增加;当预变形量不低于35%时,合金内Ni4W相的体积分数较大,且分布均匀,尺寸为3~13 nm,析出强化效果较好。通过时效前的预变形处理可将大量位错引入到合金基体中,随着预变形量的增加,合金的位错形态由低密度位错—位错线逐渐转变为高密度位错—胞状结构,形变强化作用增强。Effect of pre-deformation on the mechanical properties and microstructure of DT740 high-density alloy were investigated systematically by means of Rockwell hardness tester,room-temperature tensile tester,scanning electron microscope,transmission electron microscope and X-ray diffractometer.The results show that with the increase of pre-deformation,the strength and hardness of the DT740 alloy increase gradually.When the pre-deformation reaches to 35%,the strength and toughness of the alloy present the best strength plasticity combination,and the tensile fracture surface shows microvoid coalescence fracture.The pre-deformation promotes the precipitation of Ni4W phase during aging,and with the increase of pre-deformation,the number of Ni4W and dislocation density of the alloy increase.When the pre-deformation degree is not less than 35%,the Ni4W phase in the alloy has large volume fraction and uniformly distributed with the size of 3-13 nm,leading to good precipitation strengthening effect.The pre-deformation before aging can introduce a large number of dislocations into the matrix.With the increase of pre-deformation,the dislocation morphology changes from low density dislocation line structure to high density dislocation cellular structure,which enhances the effect of deformation strengthening.

关 键 词：DT740高密度合金 预变形 析出强化 形变强化 

分 类 号：TG146.4[一般工业技术—材料科学与工程]