形变热处理对定向凝固Cu-Ni-Sn合金组织与性能的影响  

Effect of thermomechanical treatment on microstructure and properties of directionally solidified Cu-Ni-Sn alloy

作　　者：孙子强 肖柱[1] 李翰冬 张玉芳 贾延琳[1] 甘雪萍[2] SUN Zi-qiang;XIAO Zhu;LI Han-dong;ZHANG Yu-fang;JIA Yan-lin;GAN Xue-ping(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Powder Metallurgy Research Institute,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学粉末冶金研究院,湖南长沙410083

出　　处：《材料热处理学报》2025年第2期130-139,共10页Transactions of Materials and Heat Treatment

基　　金：国家重点研发计划(2021YFB3700700);国家自然科学基金(52071342)。

摘　　要：通过ProCAST软件模拟了定向凝固温度场分布,优化了定向凝固工艺,制备了φ13 mm Cu-15Ni-8Sn合金棒材。首先对合金进行固溶处理,随后进行冷拉拔变形及时效处理。采用光学显微镜、透射电镜、显微硬度仪和力学试验机等研究了合金经不同工艺处理后的组织和性能。结果表明:固溶态棒材经65%冷拉拔变形后,硬度从121 HV上升到了285 HV,平均晶粒尺寸由15.7μm下降到0.94μm。变形态合金组织呈纤维状,形成较强的<111>//X_(0)方向的丝织构;变形态合金线材在380℃时效过程中,先发生调幅分解,然后析出DO_(22)有序相,60 min时合金硬度达到峰值399 HV,抗拉强度为1446 MPa;时效时间继续延长,进入过时效态,开始析出长条状不连续析出相(DO_(3)相),其长大形成层片状结构,导致合金性能急剧下降。The temperature field distribution of downward directional solidification was simulated using ProCAST software,and the downward directional solidification process was optimized to prepare φ13 mm Cu-15Ni-8Sn alloy bars.Firstly,the alloy was subjected to solution treatment,followed by cold drawing deformation and aging treatment.Microstructure and properties of the alloy after different process treatments were studied by means of optical microscope,transmission electron microscopy,microhardness tester and mechanical testing machine.The results show that after 65% cold drawing deformation,the hardness of the solution treated alloy bar increases from 121 HV to 285 HV,and the average grain size decreases from 15.7 μm to 0.94 μm.The microstructure of the deformed alloy is fibrous and forms a strong fiber texture in the <111>//X_(0) direction.During the aging at 380 ℃,the deformed alloy wire undergoes spinodal decomposition first,and then the DO_(22) ordered phases precipitate.After aging at 380 ℃ for 60 min,the hardness of the alloy reaches peak value of 399 HV and the tensile strength is 1446 MPa.As the aging time continues to increase,the over aging of the alloy occurs and elongated discontinuous precipitates(DO_(3) phase) begins to precipitate.These precipitates grow and form a lamellar structure,leading to a sharp decline in the alloy's performance.

关 键 词：CU-15NI-8SN合金 定向凝固 力学性能 冷拉拔 

分 类 号：TG146.1[一般工业技术—材料科学与工程]