摘要
采用选区激光熔化技术制备Inconel 718合金,并对沉积态试样进行固溶+双时效热处理。通过扫描电镜(SEM)、透射电镜(TEM)分析热处理前后合金的微观组织演化,并利用装配于扫描电镜的原位拉伸测试平台对合金拉伸变形行为及裂纹扩展机制进行研究。结果表明:与沉积态相比,经固溶+双时效后,合金的Laves相溶解,析出大量δ相,合金的屈服强度和抗拉强度分别提高了74.19%和41.35%,但伸长率明显下降;在原位拉伸变形过程中,主裂纹都以穿晶和沿晶两种方式扩展,但与沉积态相比,固溶+双时效态合金的沿晶裂纹占比明显增多。这主要是由于针状δ相在晶界附近的析出阻碍了位错运动,提高了合金的强度,但同时也增加了沿晶开裂的可能性,使试样裂纹倾向沿晶界扩展。
Inconel 718 alloy was fabricated using selective laser melting(SLM)technology,and the as-deposited samples were solution+double aged(SA).The microstructure evolutions of the alloy before and after heat treatment were analyzed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The tensile deformation behavior and crack propagation mechanisms were investigated through an in-situ tensile testing platform integrated with SEM.The results show that,compared to the as-deposited state alloy,SA alloy exhibits complete dissolution of the Laves phase and significant precipitation ofδphase.Consequently,the yield strength and tensile strength of SA alloy increase by 74.19%and 41.35%,respectively,but the elongation shows a marked decrease.During in-situ tensile deformation,the main crack propagates through both transgranular and intergranular modes.However,the proportion of intergranular cracks notably increases in the SA alloy compared to the as-deposited state alloy.This phenomenon is primarily attributed to the precipitation of needle-likeδphases near grain boundaries.These precipitates enhance the strength by impeding dislocation motion,while increasing susceptibility to intergranular cracking,thereby driving cracks to propagate preferentially along grain boundaries.
作者
郑留伟
种博文
汪英芝
申蕾蕾
刘奋成
鲁辉虎
ZHENG Liuwei;CHONG Bowen;WANG Yingzhi;SHENG Leilei;LIU Fencheng;LU Huihu(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Center for Analytical Testing and Instrument Sharing,Taiyuan University of Technology,Taiyuan 030024,China;National Defense Key Discipline Laboratory of Light Alloy Processing Science and Technology,Nanchang Hangkong University,Nanchang 330063,China;School of Mechanical Engineering,North University of China,Taiyuan 030051,China)
出处
《中国有色金属学报》
北大核心
2025年第8期2690-2704,共15页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(52361010)。
作者简介
通信作者:郑留伟,副教授,博士,电话:13327461120,E-mail:zhengliuwei@tyut.edu.cn。
