Abstract One of the challenges encountered in the industrialization of new single-crystal superalloys parts (like high-pressure turbine blades and vanes for aircraft engines) is to limit the mechanical stresses during the solidification and cooling of the metal. In order to accurately predict the viscoplastic flow as well as the thermo-mechanical behaviour of Ni-based superalloy during its cooling, in this study a thermodynamically-consistent thermo-elasto-viscoplastic model was developed. This model takes into account the solid-liquid transition occurring in the material during the cooling phase. This is done by introducing a compressible-type viscoplastic yield function based on appropriate equivalent stress depending on volume fraction of the solid phase formed by the propagation of dendrites inside the liquid phase of the material. This model was implemented in Abaqus/Standard© F.E. code and applied to the identification of material parameters of Ni-based superalloy using isothermal tensile-relaxation tests driven for different strain rates and temperatures. First, anisothermal tensile-compression test was simulated on a single integration point. A comparison of the experimental and numerical stress-strain response partially validate the model. Second, a benchmark test involving casting of a rectangular Ni-based superalloy bar in a sand mold was simulated and analyzed.

中文翻译：

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用于镍基高温合金部件凝固和冷却模拟的热机械模型

摘要 新型单晶高温合金部件（如飞机发动机的高压涡轮叶片和轮叶）工业化面临的挑战之一是限制金属凝固和冷却过程中的机械应力。为了准确预测镍基高温合金在冷却过程中的粘塑性流动和热机械行为，本研究开发了热力学一致的热弹粘塑性模型。该模型考虑了材料在冷却阶段发生的固液转变。这是通过引入可压缩型粘塑性屈服函数来实现的，该函数基于适当的等效应力，具体取决于材料液相内枝晶传播形成的固相体积分数。该模型在 Abaqus/Standard© FE 代码中实现，并应用于使用针对不同应变率和温度驱动的等温拉伸松弛试验来识别镍基高温合金的材料参数。首先，在单个积分点上模拟了非等温拉伸-压缩试验。实验和数值应力应变响应的比较部分验证了该模型。其次，模拟和分析了在砂模中铸造矩形镍基高温合金棒的基准测试。实验和数值应力应变响应的比较部分验证了该模型。其次，模拟和分析了在砂模中铸造矩形镍基高温合金棒的基准测试。实验和数值应力应变响应的比较部分验证了该模型。其次，模拟和分析了在砂模中铸造矩形镍基高温合金棒的基准测试。