中文摘要：

利用热/力模拟试验机,在950~1200℃对未均匀化处理和均匀化处理的试样进行高温压缩试验。结果发现,在各种变形温度下,经均匀化处理后,800合金热变形过程中的流变应力下降,屈服应力降低;热变形后的试样均未发现动态再结晶组织,均匀化处理对高温流变过程没有影响;均匀化处理改变了晶界碳化物形貌,晶界碳化物的形貌由层片状变为颗粒状。分析认为,热变形过程中,碳化物的形貌直接决定材料高温变形时的屈服应力,相比层片状碳化物,颗粒状碳化物导致变形过程形成低密度的位错,降低了合金高温变形抗力,引起高温屈服强度的下降。

英文摘要：

High temperature compression tests were carried out on Thermorester-W machine for the as-cast specimens and homogenization treated specimens in the deformation temperature range of 950℃to 1200℃. Experimental results show that, among various kinds of deformation temperature, after homogenization treatment the flow stress of 800 alloy declines,the yield stresses decrease; after hot deformation all specials do not occur dynamical crystallization, homogenization treatment has no effect on high temperature flow processes; homogenization treatment changes the morphologies of carbide precipitations on the grain boundary from lamellae to particles. Analysis suggests that, during the process of hot deformation,the morphology of carbide directly determines the yield stress. Compared with lamellae, particle carbides lead to the formation of low dislocation density during the deformation process, which drops the flow stress and decreases the yield stresses.