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通过蠕变性能测试和组织形貌观察,研究了高钨K416B镍基合金高温蠕变期间析出相的演化行为.结果表明,铸态合金中g’相的尺寸不均匀,条状MC碳化物在枝晶间区域呈汉字型分布;在施加应力的高温蠕变期间,细小M6C碳化物可在形变基体中不连续析出,热力学分析认为:在应力诱导作用下,元素C偏聚在应力集中处,与W等碳化物形成元素结合,促使细小M6C相自基体中析出;同时,条状MC碳化物表面形成沟槽,并逐渐分解蜕变成粒状M6C相,其中,在条状MC相表面形成的附加应力是促使MC相不断溶解和发生球化的主要原因.
The evolution behavior of the precipitated phase during high temperature creep of high-tungsten K416B nickel-based alloy was investigated by creep test and microstructure observation.The results show that the size of g ’phase in the as-cast alloy is not uniform, During the high temperature creep stressing, fine M6C carbides can not precipitate continuously in the deformed matrix. According to the thermodynamic analysis, the element C is segregated in the stress concentration place under the stress-induced action, And W and other carbide forming elements, prompting the small M6C phase precipitated from the matrix; the same time, the formation of grooves on the surface of the strip MC carbide, and gradually degenerated into granular M6C phase, which formed in the strip surface MC phase addition Stress is the main reason that causes the MC phase to dissolve and spheroidize.