δ相对一种高Nb镍基粉末高温合金热变形行为的影响

    Influence of δ Phase on Hot Deformation Behavior of A Ni-based Powder Superalloy with High Nb Content

    • 摘要: 随着航空发动机推重比的提高,对高温转动件的承温能力及性能稳定性提出了更高要求。常见的γ/γ'体系高温合金在800℃以上强度会迅速衰减,因此引入高温下更加稳定的δ相被视为提升材料承温能力的一条技术路线。通过开展系统的等温热压缩试验和组织分析研究了一种含δ相的高Nb镍基粉末高温合金的热变形行为。结果表明,热变形前通过热处理在材料中引入δ相,可以显著促进材料的再结晶程度,从而在较低的变形温度和较高的应变速率下获得细小均匀的组织。预先析出的δ相还能阻碍大变形过程中表面微裂纹向内扩展。该结果可以用于新型高强度镍基粉末高温合金的研制和锻造工艺设计。

       

      Abstract: With the improvement of the thrust weight ratio of aero-engine, higher requirements are put forward for the temperature bearing capacity and performance stability of high temperature rotating parts. The strength of the common γ/γ’system superalloy decreases rapidly over 800℃, so the introduction of a more stable δ phase at high temperature was regarded as a technical route to improve the temperature bearing capacity of the material. The hot deformation behavior of a high Nb nickel-based powder superalloy containing δ phase was studied by systematic isothermal compression test and microstructure analysis. The results show that the introduction of the δ phase into the material before thermal deformation can significantly promote the recrystallization of the material, thus obtaining fine homogeneous microstructure at lower deformation temperature and higher strain rate. The pre-precipitated δ phase also hinders the inward expansion of surface micro-cracks during large deformation. The results can be used in the development of a new high-strength nickel-based powder superalloy and the forging process design.

       

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