中文摘要：

采用热装法制成了25Cr5MoA钢／Q235固-固复合轴坯料，研究了复合轴挤压成形以及热处理后的界面组织、Cr元素扩散、显微硬度以及结合强度。结果表明：由于采用热装，在结合界面上出现了接近于连续分布的氧化物层，当挤压比为5．6时，挤压变形无法消除氧化皮的影响。结合界面的氧化皮对元素扩散起到阻碍作用，使Cr元素在界面附近Cr元素分布出现跳跃；与挤压态相比，随着保温时间的延长，25Cr5MoA钢与Q235钢结合界面的氧化物层有所改善。当保温时间大于60min时，界面附近硬度峰值消失，显微硬度连续变化区间扩大；复合轴结构上所具有的特点，使其即使结合强度较低，也不易产生剥离，经过后续热处理，通过元素的扩散过程，提高复合轴的结合强度。

英文摘要：

The influence of extrusion and subsequent heat treatment process of the 25CrSMoA/Q235 clad shaft prepared by means of hot charging on interface microstructure,diffusion of Cr, micro-hardness and bonding strength was investigated, the results showed that an oxide layer which almost distributed continuously was formed in the interface of clad shaft produced by means of hot charging, the effects of oxide could not be eliminated by extrusion deformation when the extrusion ratio was 5.6. The oxide layer of the bonding interface impeded distribution of Cr, which made the distribution of Cr skip; during the heat treatment, the oxide in the bonding interface was improved with holding time increasing. When the holding time was above 60 minutes, the peak of hardness disappeared and the continuous change region of micro-hardness increased near the interface. The characteristics possessed by the clad shaft made the shaft difficult to be peeled. The bonding strength of the clad shaft could be increased after hot treatment and the diffusion of alloying elements.