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.
作者
张胜
王春旭
姜庆伟
刘少尊
李建新
厉勇
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)
出处
《金属热处理》
CAS
CSCD
北大核心
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)
关键词
DT740高密度合金
预变形
析出强化
形变强化
DT740 high density alloy
pre-deformation
precipitation strengthening
deformation strengthening
