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利用电子探针等手段研究了不同Ti含量对DZ68合金凝固过程和偏析的影响。结果表明,随合金中Ti含量的增加,合金的初凝温度和终凝温度逐渐降低,凝固温度区间逐渐增大。当Ti含量达到0.55%～1.7%之间的某一值时,铸态合金中出现(γ+γ′)共晶,并随Ti含量增加,(γ+γ′)共晶数量增加。随合金中Ti含量的增加,W的负偏析程度显著增加,Cr由正偏析元素逐渐转变成负偏析元素。在终凝前,随合金中Ti含量的增加,凝固前沿固体中的Ti含量随凝固温度下降的平均变化速率增加,而Cr含量随凝固温度下降的平均变化速率下降。
The effects of different Ti contents on the solidification process and segregation of DZ68 alloy were investigated by electron probe. The results show that with the increase of Ti content in the alloy, the initial setting temperature and the final setting temperature of the alloy gradually decrease, and the solidification temperature range gradually increases. When the Ti content reaches a certain value between 0.55% and 1.7%, (γ + γ ’) eutectic appears in the as-cast alloy and the amount of (γ + γ’) eutectic increases with increasing Ti content. With the increase of Ti content in alloy, the negative segregation degree of W increases remarkably, Cr gradually changes from positive segregation element to negative segregation element. Before the final setting, with the increase of the Ti content in the alloy, the average rate of change of the Ti content in the solidified solid with the decrease of the solidification temperature increases, while the Cr content decreases with the average change rate of the solidified temperature.