稀土对激光熔覆EA4T车轴微观组织和性能的影响

通过在FeCrNiMo粉末中添加La和Ce混合稀土粉末对EA4T钢进行激光熔覆再制造，采用SEM、EDS、XRD等方法观察熔覆层的微观组织结构，并对再制造试样进行拉伸实验。结果表明:FeCrNiMoRE合金粉末再制造试样熔覆区主要为板条马氏体、奥氏体和碳化物组成；在熔覆区La和Ce在晶界和晶内分布较均匀，并且与O、C、S元素等形成稀土夹杂物，作为碳化物非均质形核质点，起到细化晶粒的作用；再制造试样的抗拉强度为932 MPa、屈服强度为735 MPa，分别比基体提高12.56%和9.7%；其延伸率和断面收缩率与基体基本相当，断裂特征为韧性断裂。

Effect of Rare Earth on Microstructure and Performance of Laser Cladding EA4T Axle

EA4T steel was Laser cladding remanufactured by adding La and Ce mixed rare earth powder to FeCrNiMo powder. The microstructure of the cladding layer was observed by using SEM, EDS, XRD and other methods, and the remanufactured samples were tested by tensile test. The results show that the microstructure of FeCrNiMoRE alloy powder remanufactured samples is mainly composed of lath martensite, austenite and carbide in the cladding area. In the cladding zone, La and Ce are evenly distributed in grain boundaries and crystals, and form rare earth inclusions with O, C, S, etc., which act as heterogeneous nucleation particles of carbides and play a role in refining grains. Therefore, the tensile strength is 932 MPa and yield strength is 735 MPa of the remanufactured sample. They were improved 12.56% and 9.7% higher than that of the substrate, respectively. Generally, the elongation and reduction of section were similar to that of the matrix.