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<p>The 1.5 wt% platinum (Pt) addition on the microstructural stability and γ′ precipitate evolution in the 718Plus superalloy was revealed in this study. Utilizing scanning electron microscopy (SEM) and atom probe tomography (APT), it is demonstrated that Pt strongly partitions into the γ′ precipitates with a coefficient of 3.82. This enrichment kinetically suppresses the diffusion of γ′-forming elements, notably Nb, leading to a higher coarsening activation energy and a reduction in the coarsening rate of γ′ precipitates. Furthermore, the co-segregation of Pt and Nb at the γ/γ′ interface increases the lattice misfit, which thermodynamically drives an earlier morphological transition of the γ′ precipitates from spheroidal to cuboidal at a smaller particle size. The results conclusively show that Pt changes microstructural stability through dual mechanisms: impeding coarsening kinetics and modulating interfacial strain to guide microstructural evolution.</p>

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Microstructural stability enhancement in Pt-modified 718Plus superalloy through coarsening and morphology control of γ′ precipitates

  • 期刊论文

  • 发表日期：

    2026年4月29日

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  • Hongliang Liu,
  • Guowei Wang,
  • Lan Liu,
  • Yu Shen,
  • Minqing Wang,
  • Boning Zhang,
  • Lei Zheng

摘要

The 1.5 wt% platinum (Pt) addition on the microstructural stability and γ′ precipitate evolution in the 718Plus superalloy was revealed in this study. Utilizing scanning electron microscopy (SEM) and atom probe tomography (APT), it is demonstrated that Pt strongly partitions into the γ′ precipitates with a coefficient of 3.82. This enrichment kinetically suppresses the diffusion of γ′-forming elements, notably Nb, leading to a higher coarsening activation energy and a reduction in the coarsening rate of γ′ precipitates. Furthermore, the co-segregation of Pt and Nb at the γ/γ′ interface increases the lattice misfit, which thermodynamically drives an earlier morphological transition of the γ′ precipitates from spheroidal to cuboidal at a smaller particle size. The results conclusively show that Pt changes microstructural stability through dual mechanisms: impeding coarsening kinetics and modulating interfacial strain to guide microstructural evolution.