稀土Y_2O_3对激光熔覆Al/Fe基合金涂层的影响

采用激光熔覆技术在低碳钢表面制备了Al/Fe基合金涂层。通过Olympus金相显微镜、SEM、EDS和显微硬度测试研究了稀土Y2O3的添加对熔覆层组织结构和显微硬度的影响。结果表明:稀土Y2O3的添加,加剧了激光熔覆过程中的铝热反应,提高熔覆层凝固温度,增大熔覆层及结合区白亮带的厚度。通过与合金元素的交互作用改变了熔覆层中合金元素的分布,使合金元素含量自结合区至熔覆层表层呈增加趋势,细化了晶粒,提高熔覆层整体硬度。同时Y2O3在熔覆过程中可部分代替C的还原作用,减少C的损失,并使C和Cr大量富集于熔覆层表层,极大地提高熔覆层表层硬度。

Effect of Y_2O_3 on the Al/Fe Based Alloy Coating by Laser Cladding

The Al/Fe based alloy coating was prepared by using laser cladding.The effects of addition of Y2O3 on the microstructure and micro-hardness of cladding layer were investigated by OM,SEM,EDS and Vickers hardness.The results showed that,the addition of Y2O3 could reinforce thermit reaction,elevate solidification temperature and increase thickness of the white-light bondzone between cladding layer and matrix.Through the interaction between Y2O3 and the alloyed element during solidification,the distribution of elements in cladding layer was changed to increase from the bondzone to the surface of cladding layer,grain became refined and hardness of the whole cladding layer was enhanced.Particularly,as Y2O3 could partly replace the reduction of C,the hardness on the surface of cladding layer was remarkably enhanced by the enrichment of C and Cr on the surface of cladding layer.