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Shanghai University Multi-Physics Simulation Reveals Solid-State Cracking Mechanisms in LPBF Nickel-Based Superalloys
2026-06-10
A joint research team from Shanghai University has developed an integrated multi-physics simulation framework combining heat transfer, microstructure evolution, crystal plasticity, and crack propagation, offering a systematic approach for crack analysis and process optimization in laser powder bed fusion (LPBF) and other non-weldable superalloys. The study shows that cracks are initiated by tensile stress during the cooling stage at approximately 200°C. During the propagation stage, fine equiaxed grain boundaries effectively inhibit crack growth, while columnar grains provide continuous propagation paths. Reducing scanning speed promotes the transition from columnar to equiaxed grains, thereby suppressing solid-state cracking. Experimental validation with CM247LC alloy demonstrated a reduction in crack density from 1.35 to 0.05 mm²/mm², a decrease of 96%.
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上海大学多物理场仿真揭示LPBF镍基高温合金固态裂纹机理
上海大学联合研究团队建立了集成传热、微观组织演化、晶体塑性和裂纹扩展的一体化多物理场仿真框架，为激光粉末床熔融（LPBF）及其他非焊接性高温合金的裂纹分析和工艺优化提供了系统方法。研究表明，裂纹在冷却阶段约200°C时由拉应力引发；扩展阶段中，细小等轴晶界可有效抑制裂纹扩展，而柱状晶则提供连续扩展通道。降低扫描速度可促进柱状晶向等轴晶转变，从而抑制固态裂纹。CM247LC合金实验验证，裂纹密度从1.35降至0.05 mm²/mm²，降幅达96%。