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采用区域熔炼液态金属冷却超高温度梯度定向凝固法(ZMLMC),研究凝固速率对一种镍基高温合金微观组织的影响。结果显示:在温度梯度基本不变的条件下,随着凝固速率的提高,枝晶结构逐渐细化,一次枝晶间距λ1与二次枝晶间距λ2减小,且λ1和λ2分别与V-1/4和V-1/2呈线性关系;γ’相尺寸随凝固速率的提高而减小,形貌逐渐趋向于立方状,而在同一速率下,枝晶干的γ’相形状相对较规则,接近立方形,枝晶间的γ’相则趋于无规,其尺寸也较枝晶干区域更为粗大;γ/γ’共晶尺寸随凝固速率的提高而减小,分布趋于弥散,但总的体积分数变化不大。
The influence of solidification rate on the microstructure of a nickel-base superalloy was investigated by ZSMMC, a zone-melting liquid metal cooling ultrahigh temperature gradient directional solidification method. The results show that the dendritic structure is refined with the increase of the solidification rate under the condition of almost constant temperature gradient. The first and second dendrite spacing λ1 and λ2 decrease with the increase of the solidification rate, and λ1 and λ2 are the same as V- 1/4 and V-1/2 showed a linear relationship. The γ ’phase size decreased with the increase of the solidification rate, and the morphology tended to be cubic. However, at the same rate, the shape of γ’ Rule, near the shape of the cube, the γ ’phase of the dendrite tends to be random and its size is also larger than that of the dendritic dry zone. The γ / γ’ eutectic size decreases with the increase of the solidification rate, and the distribution tends to Diffuse, but the overall volume fraction changed little.