摘要
为了对7075铝合金进行表面强化,采用激光熔注技术,以氩气同轴送粉的方式注入Cr-Al粉末,制备了Cr-Al/7075梯度复合材料层。采用金相显微镜(OM)和扫描电镜(SEM)观察熔注层的宏观形貌和微观结构,用X-射线衍射(XRD)进行物相分析,并测试了显微硬度。探索激光功率对复合材料层的影响。结果表明:通过激光熔注的方法制备了Cr-Al/7075复合材料层,增强颗粒沿熔池深度方向呈梯度分布,与其显微硬度分布一致。随着激光功率提高,复合材料层的宽度和厚度增加,增强体含量增加,Cr-Al反应生成物的种类和含量也逐渐增多。增强体的含量以及与基体的界面反应程度都会对硬度造成影响,当功率为1.4 kW时,复合材料层的表面硬度最大,为427.5HV0.2,是7075铝合金基体的3.01倍,此为最佳功率。7075铝合金表面得以强化的主要原因是增强体承载。
In order to strengthen the surface of 7075 aluminum alloy,Cr-Al powder was injected by laser melting and argon coaxial powder feeding.And the Cr-Al/7075 gradient composite layer was prepared.The macroscopic morphology and microstructure of the injec-tion layer were observed by means of metallographic microscope(OM)and scanning electron microscope(SEM).The phase was analyzed by X-ray diffraction(XRD)and the micro-hardness was measured.And thus the effect of laser power on the composite layer was explored.The results show that the Cr-Al/7075 composite layer is prepared by laser cladding,and the enhanced particles are distributed in gradient along the depth of the molten pool,consistent with their mierohardness distribution.With the increase of laser power,the width and thickness of the composite layer increase,the content of the reinforcement increases,and the types and content of Cr-Al reaction products gradually increase.The content of the reinforcement and the interfacial reaction degree with the matrix will influence the hardness.When the power is 1.4 kW,the surface hardness of the composite layer reaches the maxi-mum of 427.5HV2,which is 3.01 times of the 7075 aluminum alloy matrix.And it is the best power.The main reason for the surface enhancement of 7075 aluminum alloy is the bearing capacity of the reinforcement.
作者
王秋林
黄德明
朱金波
李勇
赵龙志
WANG Qiu-lin;HUANG De-ming;ZHU Jin-bo;LI Yong;ZHAO Long-zhi(Chengdu Aeronautic Polytechnic,Chengdu 610100,China;School of Mechanical,Electrical and Vehicle Engineering,Chongqing Jiaotong University,Chongqing 400074,China;School of Materials Science and Engineering,East China Jiao Tong University,Nanchang 330013,China)
出处
《轻合金加工技术》
CAS
2021年第1期78-83,共6页
Light Alloy Fabrication Technology
基金
国家自然科学基金(51761012)
四川省教育厅资助项目(18ZB0058)
成都航空职业技术学院重点科研项目(061902)。
