混粉准干式电火花表面强化TC4钛合金强化层组织与性能  

Microstructure and Properties of Strengthening Layer of TC4 Alloy Surface Strengthened by Powed-mixed Near-dry EDM

作　　者：李敏[1,2] 蔡兰蓉 Li Min Cai Lanrong(School of Mechanical Engineering, Tianjin University of Technology and Education Tianjin Key Laboratory of High Speed Cutting and Precision Machining)

机构地区：[1]天津职业技术师范大学机械学院 [2]天津市高速切削与精密加工重点实验室

出　　处：《特种铸造及有色合金》2017年第9期1014-1017,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51301121);天津市优秀青年教师计划资助项目(RC14-38);天津职业技术师范大学校级项目(KYQD10012);天津科技创新体系及平台建设计划资助项目(14TXGCCX00011);天津市高等学校创新团队培养计划资助项目(TD12-5043);天津市高校学科领军人才培养计划资助项目(RC14-02);天津科技创新体系及平台建设计划资助项目(14TXGCCX00011);天津市科技计划资助项目(15ZXZNGX00160);天津市高校实验实训教学示范中心资助项目(059-JX120304)

摘　　要：利用混粉准干式电火花表面强化技术对TC4钛合金进行表面强化。工作介质中混入B4C粉末,工具电极选用石墨电极,在其表面形成富含C、B、Ti、Al等元素的强化层来改善钛合金表面的硬度。结果表明,强化后合金表面形成一层致密的、呈菊花瓣状层叠式组织的强化层,与基体结合良好,电流增大菊花瓣状晶粒明显增大;经峰值电流为3.7和6.6A的电火花强化后,强化层硬度(HV)由强化处理前的312分别提高至899和1 039。XRD分析表明,强化层中出现了TiC、TiB、B_8C、Al_3BC、Al_3Ti和Al_5Ti_2等相,电流增大至6.6A时还出现了Al_(3.3)Ti亚稳相,且Ti-Al化合物相含量明显增多,实现了对钛合金表面的混杂强化。The electric spark deposition method was used to strengthen TC4 alloy surfaces under powdermixed near-dry EDM.Through the medium mixed with B4 C powder,graphite electrode as the tool electrode,the hardness of titanium alloy surface was improved by forming strengthening layer with enriched in C,B,Ti and Al phases.The results indicate that dense,well combined with matrix and cascade chrysanthemum petal-like microstructure can be observed,and with increasing in current,the grain size is increased.It is found that the micro-hardness of about 899 HV and 1 039 HV can be obtained when the current is 3.7Aand 6.6A,which is improved significantly compared with that of the original alloy（about 312HV）.XRD results reveal that TiC,TiB,B8C,Al3BC,Al3Ti and Al5Ti2 phases can be observed in the strengthening layer.The metastable phase of Al（3.3）Ti appears,and the phase of Ti-Al intermetallic compound is increased significantly with the current of 6.6A.

关 键 词：混粉准干式电火花 TC4钛合金 组织 显微硬度 相组成 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG174.442.2[金属学及工艺—金属材料]