摘要
利用定量分析手段建立INCONEL718高温合金的均匀化模型。采用金相法确定d406mm铸锭的初熔温度,结果表明其初熔温度为1170～1180°C。采用两阶段均匀化热处理消除枝晶显微偏析。为了定量预测 Laves相的溶解过程,提出一个和时间、温度相关的均匀化模型。在铸态组织的所有偏析元素中,Nb和Ti为偏析程度最大的正偏析元素。然后,分别计算在1140 °C时各合金元素的扩散系数,并与另外两种常见的含铌高温合金进行比较。
Quantitative analysis was employed to establish reasonable and practical homogenization model of INCONEL718 superalloy. Metallographic method was applied to determining the incipient melting temperature. The result shows that the incipient melting temperature of d406 mm INCONEL718 ingot is situated between 1 170 ℃ and 1 180 ℃. In order to predict the elimination process of Laves phase in quantity, a time and temperature dependent homogenization model was proposed. Among all the elements in the as-cast microstructure, Nb and Ti are the most positive segregated elements. The diffusion coefficients of alloying elements at 1 140 ℃ were obtained by fitting the linear relationship between In δ （δ residual segregation index） and time. The calculation results of diffusion coefficients were compared with other two commercial Nb-bearing superalloys.
基金
Project (08dj1400402) supported by the Major Program for the Fundamental Research of Shanghai Committee of Science and Technology,China
