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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。
High-temperature compression tests were performed on the unhomogenized and homogenized specimens at 950-1200 ° C using a heat / force simulator. The results show that the flow stress decreases and the yield stress decreases during the thermal deformation of the 800 alloy after homogenization at various deformation temperatures. No dynamic recrystallization is found in the samples after hot deformation. High-temperature rheological process has no effect; Homogenization changes the grain boundary carbide morphology, grain boundary carbide morphology from the lamellar to granular. The analysis shows that the shape of carbide directly determines the yield stress when the material is deformed at high temperature during hot deformation. Compared with lamellar carbides and granular carbides, low density dislocations are formed during deformation and the high temperature deformation of the alloy is reduced Resistance, causing high temperature yield strength decline.