激光修复TC4钛合金显微组织与力学性能（英文）  

Microstructure and Mechanical Properties of Laser Repaired TC4 Titanium Alloy

作　　者：赵庄 陈静[1] 谭华[1] 赵小林[2] 黄卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]西安航空发动机(集团)有限公司,陕西西安710021

出　　处：《稀有金属材料与工程》2017年第7期1792-1797,共6页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51475380);Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(99-QP-2014)

摘　　要：以低氧TC4粉末为熔覆材料,采用激光修复技术制备了TC4钛合金面修复试样,对比研究了锻件和修复试样(沉积态)的显微组织和力学性能。结果显示:修复试样的组织宏观上分为锻件基材区、热影响区和激光沉积区,3个区域中热影响区的显微硬度最高,沉积区和锻件基材的显微硬度相当。锻件试样的强度及塑性均略高于修复试样,同时发现40%修复试样(即拉伸试样承受载荷部位横截面上沉积区所占的面积分数为40%)的强度略低于50%修复试样,塑性则高于后者。表明采用低氧TC4粉末为熔覆材料时,有利于修复试样沉积区和基材区强度和塑性的匹配,从而提高修复试样的综合性能。对拉伸断口进行扫描电镜观察发现,锻件试样拉伸失效后断口呈现出典型的韧性断裂特征,而修复试样的断口则表现复杂,从沉积区到锻件基材区呈现出解理台阶到韧窝的连续变化特征,同时断口形貌与显微组织呈现出很好的对应关系。Laser Additive Manufacturing（LAM） was employed to fabricate repaired specimens with wrought TC4 as the substrate and TC4 powders with low oxygen（O≤0.13wt%） as the cladding materials. The microstructure and mechanical properties of TC4 specimens fabricated by LAM and wrought billet were investigated comparatively. The results show that the macrostructure of the laser repaired specimen can be divided into three domains, including wrought substrate zone（SZ）, heat affected zone（HAZ） and laser deposited zone（LDZ）. The LDZ microhardness is equal to that of the SZ basically. And the HAZ microhardness is higher than that of both the LDZ and SZ slightly. The results of room temperature tensile test show that the strength and ductility of the wrought specimen are slightly higher than that of the laser repaired specimens. Meanwhile, the strength of the laser repaired specimen with repair ratio of 40%（i.e. area fraction of the LDZ on the transverse section of tensile specimen within gauge part is 40%）is slightly lower than that of 50% repaired specimen, but the ductility is higher than the latter. Therefore it is favorable to match the strength and ductility of the wrought substrate with the LDZ with low oxygen TC4 powders as the cladding materials, so as to improve the comprehensive properties of laser repaired TC4 titanium alloy. The wrought specimen tensile fracture presents a typical ductile characteristic, and the repaired specimen shows a complex fractograph. From the LDZ to the SZ, the tensile fracture presents a successive transformation from cleavage step to dimple fracture. It can be seen that there is a good corresponding relationship between the fracture morphology and the microstructure of the tensile specimens.

关 键 词：激光修复 钛合金 组织 机械性能 断裂机制 

分 类 号：TG146.23[一般工业技术—材料科学与工程]