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本文在前一工作的基础上,研究一种Nimonic75型镍基合金高温蠕变第一和第二阶段(着重第一阶段)内的位错结构。蠕变温度800℃,应力8kg/mm~2。二毫米厚板材试样经过不同蠕变量后,制备成薄膜进行观察。所用的电子显微镜是JEM——200CX型。在未进行蠕变的试样中,很少观察到位错。在蠕变第一阶段内,观察到大量的零散位错。在蠕变第二阶段内,这些位错发生聚集,并形成亚结构边界。在蠕变第一和第二阶段,都很少观察到位错塞积。对蠕变第一阶段内形成的这些零散位错,进行了较多的观察和分析。观察和分析表明,它们一般不处在滑移面上,并且大多是混合型位错。
Based on the previous work, this dissertation studies the dislocation structure in the first and second stages of high temperature creep of Nimonic75 nickel-based alloy, focusing on the first phase. Creep temperature 800 ℃, stress 8kg / mm ~ 2. Two millimeters thick plate samples after different creep amount, prepared as a thin film for observation. The electron microscope used is the JEM-200CX type. In samples that did not creep, few dislocations were observed. During the first phase of creep, a large number of scattered dislocations were observed. During the second phase of creep, these dislocations aggregate and form sub-structure boundaries. Dislocation accumulation is rarely observed in the first and second stages of creep. The scattered dislocations formed during the first phase of creep were observed and analyzed. Observations and analyzes show that they are generally not located on slip planes and are mostly mixed dislocations.