The newly designed ingot-metallurgy nickel-based superalloy SDZhS-15 intended for disc applications at operating temperatures up to 800–850 °C was subjected to homogenization annealing and canned forging at subsolvus temperatures, followed by solid solution treatment and ageing. Mostly a fine-grained recrystallized microstructure was obtained in the forgings. It was revealed that post-forging solid solution treatment at T > (T_s-50), where T_s is the γ′ solvus temperature, led to a significant γ grain growth, which in turn led to a decrease in strength and ductility of the superalloy. The solution treatment at (T_s-60)–(T_s-50) allowed to save fine γ grains (d_γ = 10–20 μm) and to provide the formation of secondary γ′ precipitates with a size of around 0.1 μm. In the forged and heat-treated conditions, the superalloy demonstrated superior mechanical properties, particularly excellent creep resistance at 650–850 °C in the stress range of 400–1200 MPa. Microstructure examination of the creep-tested samples showed that a decrease in the creep resistance at 850 °C can be associated with enhanced diffusivity along γ grain and γ/γ′ interphase boundaries leading to formation of cracks along the boundaries. In spite of the heavy alloying, the topologically close-packed phases were not detected in the superalloy, including in the creep tested samples.

中文翻译：

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锻造和热处理对重合金锭冶金镍基高温合金组织和力学性能的影响

新设计的锭冶金用镍基高温合金SDZhS-15（适用于在800-850°C的工作温度下进行圆盘加工）经过均质退火，并在低于固溶温度的条件下进行罐头锻造，然后进行固溶处理和时效。大多数情况下，在锻件中获得了细晶粒的重结晶组织。结果表明，在T >（T _s -50）时的锻造后固溶处理（其中T _s是γ'固溶温度）导致明显的γ晶粒长大，进而导致强度和延展性降低。超级合金。（T _s -60）–（T的固溶处理_š -50）允许保存细γ晶粒（ d _γ = 10-20微米），并提供次级的形成γ'析出物的尺寸约为0.1微米。在锻造和热处理条件下，高温合金具有优异的机械性能，特别是在650-850°C的应力范围（400-1200 MPa）中具有出色的抗蠕变性。对蠕变测试样品的微观结构检查表明，在850°C下抗蠕变性能下降可能与沿γ晶粒和γ / γ'的扩散率增强有关。相间边界导致沿边界形成裂纹。尽管发生了严重的合金化，但在高温合金（包括蠕变测试的样品）中未检测到拓扑密排相。