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氧化钇颗粒增强钨板在激光热负荷加载下的损伤及组织演化

Damage and microstructure evolution of yttria particle reinforced tungsten plates under laser thermal shock

  • 摘要: 采用粉末冶金技术结合轧制工艺制备不同压下量的氧化钇颗粒增强钨板,并对不同温度等温退火实验得到的不同再结晶体积分数的样品进行瞬态激光热冲击实验,研究长期稳态热负荷引起的再结晶与瞬态热冲击协同作用下的表面损伤和显微组织演化。结果表明,在瞬态热冲击的作用下,样品表面发生开裂、熔化等损伤,再结晶过程会加速裂纹变宽、熔化区域变大,降低了材料抵抗瞬态热负荷的能力。在相同功率密度下,67%轧制量的样品明显比50%轧制量样品的损伤程度低,前者具有较好的抗热冲击性;两种样品熔化区的晶粒主要由大量柱状晶组成,其柱状晶晶粒的大小与之下面的初始基体晶粒有很大关系,轧制态样品熔化区中的柱状晶晶粒较细且多,而完全再结晶样品的晶粒较粗。

     

    Abstract: Yttria particle reinforced tungsten plates with different thickness reduction were prepared by powder metallurgy technology combined with rolling process. The prepared samples with different recrystallization volume fractions were subjected to transient laser thermal shock experiments to study the surface damage and microstructure evolution under the synergistic effect of recrystallization caused by long-term steady-state heat load and transient thermal shock. In the results, the cracks, melting, and other damages occur on the sample surface because of the thermal shock loading. Moreover, the recrystallization process would accelerate the widening of cracks and the enlargement of melting area, which greatly reduces the ability of the materials to resist transient heat loading. Under the same power density, the damage level of the samples with 67% thickness reduction is obviously lower than that with 50% thickness reduction, and the former has better thermal shock resistance; the molten zones of these two samples are composed by the columnar grains, which are associated with the grain size of the initial matrix below, and the columnar grains formed in rolled samples are finer and numerous, while those of the fully recrystallized samples are coarser.

     

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