700℃热循环冲击对Stellite12钴基合金组织以及折弯强度的影响  

Effects of thermal cycling shock at 700 ℃ on microstructure and flexural strength of Stellite12 cobalt-based alloy

作　　者：张海燕[1] 车洪艳[2] 曹睿[1] 刘国辉[2] 陈剑虹[1] ZHANG Hai-yan CHE Hong-yan CAO Rui LIU Guo-hui CHENJian -hong(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metal, Lanzhou University of Technology, Lanzhou 730050, China Advanced Technology and Materials Co Ltd,Beijing 100086, China)

机构地区：[1]兰州理工大学有色金属先进加工与再利用省部共建国家重点实验室,甘肃兰州730050 [2]安泰科技股份有限公司,北京100086

出　　处：《材料热处理学报》2017年第2期61-65,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金项目(51675255)

摘　　要：通过对Stellite12钴基合金在700℃下进行热循环冲击试验,结合扫描电镜组织观察、能谱分析、X射线衍射相分析、硬度分析以及弯曲试验,对Stellite12热循环冲击前后的组织、硬度、裂纹出现情况及折弯强度进行研究。研究发现:冲击前后Stellite12钴基合金的组织和硬度并未发生较大变化,WC相的边缘出现同成分的絮状扩散物。随着热冲击次数的增多,材料出现微裂纹且微裂纹起源于边缘,并不断扩展,最终形成裂缝。而材料的折弯强度却在75次热循环冲击后大幅降低,同时统计折弯断面上热冲击过程中出现裂纹的区域所占面积比率发现:随着面积比率的增大折弯强度降低,强度大幅降低的临界面积比率为23%。Thermal cycling shock test of Stellitel2 cobalt-based alloy was carried out at 700 ℃. The microstructure, hardness and flexural strength of the alloys in thermal cycling shock tests were investigated by scanning electron microscopy （SEM） , energy diffraction spectrum （EDS） analysis, X-ray diffraction （XRD） phase analysis, hardness and bending tests. The results show that the microstructure and hardness of the Stellitel2 cobalt-based alloy do not change signifieantly before and after the thermal cycling shock. Congruent floeeulent diffusion phase appears at the edge of WC phase after thermal cycling shock. With the increase of cycling number of thermal shock, micro- cracks which originate from the edge appear, and continue to extend, and eventually form the eraek. The flexural strength of the alloy is greatly reduced after thermal cycling shock for 75 times. Meanwhile, the statistics of percentage of the cracks produced during the thermal shock processes on the fracture surface indicate that flexural strength decreases with the increase of percentage of the cracks, and the critical percentage of the cracks that results in sharp reduction of flexural strength is 23%.

关 键 词：Stellite12 热循环冲击 裂纹 折弯强度 

分 类 号：TG146.1[一般工业技术—材料科学与工程]