| 摘要: |
| 针对6082铝合金的磨损、腐蚀、掉块等损伤，采用CMT (Cold metal transfer)电弧增材再制造技术和自主研发的Al-Si-Cr-Er丝材在其表面制备了单层多道、多层单道及多层多道成形层。综合运用金相显微镜、扫描电子显微镜、万能力学实验机、电化学工作站等分析成形层微观组织并评价其力学及电化学等综合性能。结果表明：成形层平滑光亮，焊道和焊道之间搭接平整紧密，无气孔、热裂纹、咬边、焊瘤等缺陷，Cr及稀土元素Er的加入，有效抑制了晶粒长大，促进了成形组织细化。相较于通用ER4043丝材，Al-Si-Cr-Er成形层的平均抗拉强度达228.7 MPa，最高延伸率达13.5%，微孔聚集形韧窝断裂是其主要失效机制；自腐蚀电位提高了约0.2 V，自腐蚀电流密度降低了一个数量级，成形组织的细化和杂质元素含量的降低是其耐腐蚀性能提升的主要原因。 |
| 关键词: 铝合金 增材再制造 机理 性能评价 |
| DOI：10.11933/j.issn.1007-9289.20190227001 |
| 分类号:TG174.44 |
| 基金项目:国家重点研发计划(2018YFB1105800)；中国科协青年人才托举工程(2017NRC001) |
|
| Mechanism and Properties Evaluation of Wire and Arc Additive Remanufacturing Formation for Al-Si Aluminum Alloy |
|
WANG Xiaoming, CHANG Qing, ZHAO Yang, HAN Guofeng, QIU Liu, ZHU Sheng
|
|
National key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072, China
|
| Abstract: |
| Approaches were put forward to deal with the various damages including wear, corrosion and drop-off of 6082 aluminum alloys against environment. The CMT (Cold metal transfer) arc additive manufacturing, was proposed to prepared forming layers (single layer & multi channel, multi layer & single channel and multi-layer & multi-channel) using the homemade Al-Si-Cr-Er wires. A variety of measuring methods involving OM, SEM, universal mechanical and electrochemical tests were adopted to evaluate the mechanical and electrochemical performances of the layers. Results show that the layers are virtually smooth and bright, and the boundaries among weld channels are evident and tight. No obvious porosity, hot crack and biting weld are detected. Moreover, the addition of Cr and Er in the Al-base wire can effectively inhibit grain growth, which promotes the refinement of microstructure. The mechanical properties of the layers are greatly enhanced in comparison with layers fabricated by general ER4043 wires. For example, the average tensile strength of the layers formed by Al-Si-Cr-Er wire is 228.7 MPa and the maximum extension reaches 13.5%. Additionally, the main failure mechanisms of the layers are believed to be microporous aggregates shaped dimple. Meanwhile, the corrosion potential of the layers formed by Al-Si-Cr-Er wire increases about 0.2 V and the self-corrosion current density reduced by about 10 times. The enhanced corrosion resistance can be attributed to the refinement of grains and the reduction of impurities. |
| Key words: aluminum alloy additive remanufacturing formation mechanism properties evaluation |
