The Effect of Nb/Ti Ratio on Hardness in High-Strength Ni-Based Superalloys
The Effect of Nb/Ti Ratio on Hardness in High-Strength Ni-Based Superalloys
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DOI：
10.3390/met7030071
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发表时间：
2017-03-01
期刊：
影响因子：
2.9
通讯作者：
Reed, Roger C.
中科院分区：
文献类型：
--
作者：
Hisazawa, Hiromu;Terada, Yoshihiro;Reed, Roger C.
研究了不同Nb/Ti比的ABD-D2、D4和D 6高强度镍基高温合金的时效硬化行为和组织演变。所研究的合金具有大的体积分数和多峰尺寸分布的γ '沉淀物，使它们对固溶热处理后的冷却条件敏感。用复制加工热处理的热循环进行差示扫描量热法。这些合金的硬度随后通过纳米压痕进行评价。没有观察到Nb/Ti比影响一次和二次γ '沉淀物的尺寸和分布;然而，观察到三次γ'和沉淀物形态的差异。所有合金的纳米压痕硬度降低，一旦他们已经固溶热处理。合金表现出特定的峰值硬度。发现具有最大Nb含量的合金在所研究的合金中具有最好的硬度增加，这是由于其大的第三γ '沉淀物。
The age-hardening behaviour and microstructure development of high strength Ni-based superalloys ABD-D2, D4, and D6 with varying Nb/Ti ratios have been studied. The studied alloys have large volume fractions and multimodal size distributions of the gamma' precipitates, making them sensitive to cooling conditions following solution heat treatment. Differential scanning calorimetry was conducted with a thermal cycle that replicated a processing heat treatment. The hardness of these alloys was subsequently evaluated by nanoindentation. The Nb/Ti ratio was not observed to influence the size and distribution of primary and secondary gamma' precipitates; however, the difference in those of tertiary gamma' and precipitate morphology were observed. The nanoindentation hardness for all alloys reduces once they have been solution-heat-treated. The alloys exhibited specific peak hardness. The alloy with the greatest Nb content was found to have the best increase in hardness among the alloys studied due to its large tertiary gamma' precipitate.