抽拉速率对定向凝固镍基高温合金组织和偏析的影响

研究了抽拉速率对一种定向凝固镍基高温合金组织与偏析的影响。结果表明,随着抽拉速率的增加,固液界面由平界面向胞状,再到粗枝状,最后到细枝状的演变过程,枝晶不断细化;一次和二次枝晶间距不断变小,γ′相形貌越来越呈规则的立方体,γ′尺寸逐渐变小。元素偏析程度先增大后减小,并在100μm/s时到达峰值;共晶和碳化物尺寸均随着抽拉速率的增大而变小,碳化物和共晶体积分数随抽拉速率增大而增大。

Effect of Drawing Rate on Microstructure and Segregation of Directionally Solidified Nickel-based Superalloy

The effect of drawing rate on microstructure and segregation of a directionally solidified nickel-based superalloy was studied.The results show that with the increase of the drawing rate,the solid-liquid interface changes from the flat boundary to the cellular,then to the coarse dendritic and finally to the fine dendritic.The spacing between primary and secondary dendrites is getting smaller and smaller,and theγ′phase morphology is becoming more and more regular cube,and the size ofγ′is getting smaller and smaller.The degree of element segregation first increases and then decreases,and reaches the peak at 100μm/s.The eutectic and carbide sizes decrease with the increase of the drawing rate,and the volume fraction of carbide and eutectic integrals increase with the increase of the drawing rate.