摘要
采用激光熔化沉积的方法对AlSi10Mg增材制造,制备出致密度大于99%、抗拉强度350 MPa左右、延伸率8%的薄壁墙体试件,利用光学显微镜与扫描电镜分析了沉积态的组织。发现即使增材制造过程水氧含量(体积分数,下同)均控制在1×10^-5以下,试件内部仍存在一定的气孔缺陷,气孔均为直径100μm以下的氢气孔。进一步试验表明,环境中的氧体积分数与气孔率呈正相关关系。在保持环境湿度和温度不变的情况下,环境氧含量由1×10^-5增加到1×10^-3,气孔直径略微增大,气孔率由0.45%增大到2.71%,气孔率增加近5倍,同时抗拉强度降低100 MPa左右,降幅超过30%,延伸率降幅超过20%。最后探讨了氢气孔在激光熔化沉积制造的试件中产生的机理,给出了利用激光熔化沉积工艺制备稳定的AlSi10Mg合金的策略。
A series of AlSi10Mg alloy walls were additive manufactured by laser metal deposition(LMD) process. The density was above 99%, the tensile strength was more than 350 MPa and the elongation was about 8%. OM and SEM were utilized to observe and analyze the microstructure of as-deposited walls. Results show that even if both of water and oxygen concentration is controlled under 1×10^-5, there are some pores in the microstructure, which means the pores in LMD process are nearly impossible to eliminated. The pores are hydrogen micro pores, with diameter less than 100 μm. Further experiments show that the porosity is closely related to the oxygen concentration. Keeping the temperature and humidity constant, when the oxygen concentration rises from 1×10-5 to 1×10^-3, the porosity quadruples from 0.45% to 2.71%. Meanwhile the tensile strength decreases more than 100 MPa, falling over 30%, and the elongation reducing by over 20%. Finally, the mechanism of porosity formation was discussed. Methods to fabricate AlSi10Mg alloy with steady mechanical property by LMD process were given.
作者
李俐群
王宪
曲劲宇
陶汪
LI Liqun;WANG Xian;QU Jinyu;TAO Wang(State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2019年第3期109-114,共6页
China Surface Engineering
关键词
AlSi10Mg
激光熔化沉积
增材制造
气孔
力学性能
AlSi10Mg
laser metal deposition(LMD)
additive manufacturing
porosity
mechanical property
作者简介
通信作者:李俐群(1970-),女(汉),教授,博士,研究方向:激光增材制造与激光加工,E-mail:liliqun@hit.edu.cn。
