摘要
采用光学显微镜（OM）、透射电镜（TEM）、抗拉强度和电导率测试等方法研究了不同温度时效后大型发电机转子用Cu-Ni-Si合金槽楔组织和性能变化规律。结果表明：合金在热挤压过程中发生动态回复与再结晶,热挤压后为再结晶组织,晶粒内部有贯穿整个晶粒的退火孪晶。在时效阶段屈服强度和抗拉强度随温度变化表现为先升高后下降的趋势,在430℃时过饱和固溶体发生有序化转变和第二相析出,基体上弥散分布的细小析出相和长程有序相会阻碍位错运动,提高力学性能。在550℃时效阶段合金处于过时效状态,析出相主要为Ni2Si,已经明显长大,对位错阻碍作用减弱,合金力学性能下降,但电导率始终保持上升的趋势。随时效温度升高,试样拉伸断口形貌逐渐由解理型转变为韧窝型,表明合金塑性逐渐提高。实验结果表明,在430℃时效3 h Cu-Ni-Si合金具有最佳的综合性能,屈服强度为650 MPa,抗拉强度为760 MPa,电导率为43.2%IACS。
The effect of aging temperature on microstructure and properties of Cu-Ni-Si rotor slot wedge alloy in large generator was investigated by means of optical microscope（OM）,transmission electron microscope（TEM）,tensile strength and conductivity tests.The results indicated that after hot extrusion the Cu-Ni-Si alloy gained recrystallized structure due to the dynamic recovery and recrystallization and some grains had annealing twins which crossed through the entire grain. The yield strength and tensile strength increased firstly and then decreased as the aging temperature changed. When the aging process occurred at 430 ℃,the ordering transformation and precipitation simultaneously appeared in supersaturated Cu-Ni-Si solid solution,the long rang order phases and dispersedly distributed precipitated phases could strongly block the dislocation motion,causing a significant rise in the strength. When the aging temperature was 550 ℃,the alloy was overaged. The precipitated phase was quickly coarsening,making the dislocation blocking effect decrease. The mechanical properties gradually decreased,but the electrical conductivity still remained rising. As the aging temperature changed,the tensile fracture morphology of Cu-Ni-Si alloy was shifted from cleavage type to dimple type,which meant that the plasticity was gradually improved. It was suggested that the Cu-Ni-Si alloy obtained excellent comprehensive properties with aging treatment at430 ℃ for 3 h,and the yield strength,tensile strength and electrical conductivity of the alloy were up to 650,760 MPa and 43. 2 %IACS,respectively.
作者
朱新德
张涛
李胜利
安仲鑫
Zhu Xinde;Zhang Tao;Li Shengli;An Zhongxin(School of Materials Science and Engineering, Shandong University, Ji＇nan 250061, China;VOSS Automotive Ltd. , Ji＇nan 250061, China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2018年第6期580-585,共6页
Chinese Journal of Rare Metals
基金
山东省自主创新及成果转化专项(2014CGZH0102)
山东省自主创新专项(2013CXB60201)
山东省科技发展计划项目(2014GGX102003)资助
