时效Ag-7wt.%Cu合金的微观组织、电阻率和硬度  

Microstructure, resistivity, and hardness of aged Ag-7wt.%Cu alloy

作　　者：李蕊[1,2] 左小伟[1,3] 王恩刚[1,3] Li Rui Zuo Xiao-Wei Wang En-Gang(Key Laboratory of Electromagnetic Processing of Materials （Ministry of Education,, Northeastern University, Shenyang 110819, China School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China School of Metallurgy, Northeastern University, Shenyang 110819, China)

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,沈阳110819 [2]东北大学材料科学与工程学院,沈阳110819 [3]东北大学冶金学院,沈阳110819

出　　处：《物理学报》2017年第2期311-321,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51474066;51004038);高等学校学科创新引智计划(批准号:B07015)资助的课题~~

摘　　要：采用差示扫描量热法、X射线衍射及透射电子显微镜研究了固溶和固溶一冷轧Ag-7wt.%Cu合金在时效过程中富Cu相的析出动力学和形貌特征,同时结合电阻率和显微硬度的测量,定量对比了固溶和固溶一冷轧Ag-7wt.%Cu合金时效过程中富Cu相对电阻率和硬度的影响及其机理.研究结果表明:固溶样品中富Cu相反应温度为300℃-350℃,析出激活能为(111±1.6)kJ/mol;而固溶一冷轧样品中由于形变能的存在,富Cu相温度降低为290℃-330℃,析出激活能升高为(128±12)kJ/mol.XRD结果证实富Cu相的析出过程与时效温度有关.固溶和固溶一冷轧合金在450℃时效后均能观察到球状的富Cu相,富Cu相的析出和溶解过程对电阻率和显微硬度有显著影响.当时效温度低于450℃时,随时效温度的提高,固溶一时效样品的电阻率降低,显微硬度增加:而固溶一冷轧一时效样品的电阻率和显微硬度均逐渐降低.显微硬度除了受富Cu相的影响外,还受到位错和形变孪晶的影响.当时效温度高于450℃时,两种样品的电阻率增大,而显微硬度降低.Ag-Cu alloys are used as both decorative materials because of beautiful appearance,and conductors due to excellent combinations of strength and electrical conductivity.The strength and electrical conductivity of Ag-Cu alloy are closely related to precipitation behavior of Cu-rich phase in Ag matrix.The morphology,size and volume fraction of Curich phase have been highly concerned.In this work,a series of aging temperatures is used in both supersaturated solid-solution and cold-rolled Ag-7wt.%Cu samples to investigate the relationship between the precipitation behavior of Cu-rich phase and property by using differential scanning calorimetry（DSC）,transmission electron microscopy（TEM）,X-ray diffraction（XRD） analysis,and properties measurements（hardness and resistivity）.The DSC results of as-solidsolution Ag-7wt.%Cu alloy show a distinct exothermic precipitation reaction of Cu out of Ag matrix ranging from 300 ℃to 350 ℃,and the activation energy is estimated to be（111 ± 1.6） kJ/mol according to Kissinger equation.Because of the existence of deformation energy,the DSC results of cold-rolled Ag-7wt.%Cu sample show a distinct exothermic precipitation reaction of Cu from Ag matrix between 290 ℃ and 330 ℃,and the activation energy is（128 ± 12） kj/mol.XRD analysis indicates that the dissolved Cu in Ag is dependent on ageing temperature,and the change of solubility of Cu in Ag is calculated by XRD curve.Microstructural analysis demonstrates that spherical Cu-rich phases are precipitated from Ag-matrix at 450 ℃ in both solid-solution and cold-rolled Ag-7wt.%Cu alloys.Moreover,the banded structure of Cu-rich phase is found in the solid-solution sample after being aged at 450 ℃.The deformation twinning Ag is found in the cold-rolled sample.The precipitation and dissolution of Cu-rich phase in Ag matrix play important roles in the resistivity and microhardness.With ageing temperature increasing（ageing temperatures range from 200 to450 ℃）,the electrical resistivity of as-solid-solution

关 键 词：AG-CU合金 显微组织 电阻率 显微硬度 

分 类 号：TG146.32[一般工业技术—材料科学与工程] TG166.7[金属学及工艺—金属材料]