铪合金化对Ni-Cr-Mo合金中γ'相沉淀行为及拉伸性能的影响

Influence of Hf Alloying on Precipitation Behavior of γ' Phase and Tensile Properties of Ni-Cr-Mo Alloy

摘要:

研究了Hf对Ni-Cr-Mo合金长期热暴露后γ′相析出行为及拉伸性能的影响。结果表明，在700 ℃热暴露5000 h的过程中，Hf的加入增大了γ′相的尺寸，从而提高了Ni-Cr-Mo合金中位错剪切γ′相的临界分解剪切应力。同时，Hf元素进入γ′相中，增加了γ′与γ之间的晶格错配度，从而提高了沉淀强化效果。这2种因素共同提高了合金的强度。因此，Hf合金化可以有效地提高Ni-Cr-Mo合金在700 ℃高温下的屈服强度。

Abstract:

The influence of Hf on the precipitation behavior of γ' phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated. The results reveal that the addition of Hf increases the average diameter of γ' phases after thermal exposure at 700 ℃ for 5000 h, which enhances the critical resolved shear stress required for dislocations to shear the γ' phases in the Ni-Cr-Mo alloy. Simultaneously, element Hf incorporated into the γ' phases increases the lattice mismatch between the γ' and γ phase, thereby strengthening the coherency strengthening effect. These two factors collectively contribute to the enhanced strength of the alloy. Thus, Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700 ℃.