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本文研究了不同Mg含量的GH698合金的蠕变性能、断口形貌和组织形态。结果表明:经小炉冶炼的GH698合金,当镁含量在最佳成分范围内(0.0038～0.0065％)时,合金蠕变速率最低,蠕变断裂寿命最长,而且蠕变第Ⅲ阶段呈现出较好的塑性,持续时间较长;不含镁或镁含量过高的合金,其蠕变性能均有所下降。在蠕变过程中,Mg作为晶界强化元素,改善了晶界状态,协调晶界与晶内的变形,减缓裂纹的扩展能力,使合金的强度和塑性达到最佳的配合,从而使合金的蠕变性能明显地改善。
In this paper, the creep properties, fracture morphology and microstructure of GH698 alloy with different Mg contents were studied. The results show that when the magnesium content is within the optimum composition range (0.0038 ~ 0.0065%), the alloy GH698 alloy has the lowest creep rate and the longest creep rupture life, and the third stage of creep shows a higher creep rate Good ductility, longer duration; non-magnesium or magnesium content is too high alloy, its creep properties have declined. In the creep process, Mg as grain boundary strengthening elements, improve the grain boundary state, coordinate the grain boundary and grain deformation, slow down the expansion of the ability of the crack, the strength and ductility of the alloy to achieve the best match, so that the alloy Creep performance is significantly improved.