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提出了金属梯度结构轴的概念.研究了固-液复合的25Cr5MoA钢/Q235钢复合轴的组织、Cr元素的扩散以及结合界面附近显微硬度的变化规律.结果表明:经过挤压变形后,25Cr5MoA钢/Q235钢界面形成了良好的冶金结合,二者结合紧密,除了组织结构的差别外,二者的结合界面已经难以区分.结合界面附近Cr元素在固-液复合时得到充分扩散,并呈现出连续分布的形态.从界面向Q235钢和25Cr5MoA钢两侧±100μm范围内,硬度呈现出均匀、连续分布.经过热处理后,随着加热温度的升高和加热时间的延长,Cr元素在结合界面附近的分布更加均匀,分布曲线在界面的斜率进一步降低,使结合界面附近25Cr5MoA钢的一侧的显微硬度大幅度降低,这有利于形成化学成分、组织以及性能的梯度变化.
The concept of metal gradient structure axis was proposed.The microstructure of 25Cr5MoA steel / Q235 steel solid-liquid composite shaft, the diffusion of Cr element and the variation of microhardness in the vicinity of the interface were studied.The results show that after the extrusion deformation, The interface between 25Cr5MoA steel and Q235 steel forms a good metallurgical bond, the two are close together, and the bonding interface between the two is difficult to distinguish except for the difference in the structure of the structure. Showing a continuous distribution of morphology from the interface to both sides of Q235 steel and 25Cr5MoA steel within ± 100μm, the hardness showed a uniform and continuous distribution after heat treatment, with the heating temperature and heating time, the Cr element in The distribution near the interface is more uniform, and the slope of the distribution curve at the interface is further reduced, so that the microhardness of the side of the 25Cr5MoA steel near the bonding interface is greatly reduced, which is conducive to the formation of a gradient of chemical composition, microstructure and properties.