GH3536高温合金铸态组织特征及均匀化工艺的综合分析研究

Integrated Analysis of As-Cast Microstructural Characteristics and the Homogenization Treatment for GH3536 Superalloy

摘要:

本研究采用光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、萃取相分析、XRD以及热力学计算等多种表征方法研究了经真空感应熔炼+电渣重熔双联工艺生产的GH3536合金电渣锭的铸态组织特征,并结合均匀化热处理后组织演变及热压缩模拟实验结果进一步综合分析确定了该合金适宜的均匀化工艺。结果表明,合金内的主要偏析元素是Mo元素；电渣锭中除奥氏体基体外、还存在富Cr元素的M₂₃C₆和富Mo元素的M₆C两种碳化物。经过1180℃/48 h的均匀化热处理后,合金内大块析出相基本回溶,元素偏析显著消除,均匀化后的合金呈现出良好的热塑性。

Abstract:

In this study, the as-cast microstructure of a GH3536 electroslag ingot, produced via a vacuum induction melting plus electroslag remelting duplex process, was systematically examined using multiple characterization techniques. These included optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), extracted phase analysis, X-ray diffraction (XRD), and thermodynamic calculations. Furthermore, the microstructural evolution following homogenization heat treatment and the results of hot compression simulations were analyzed to identify an appropriate homogenization process for the alloy. The results demonstrate that molybdenum (Mo) is the primary segregating element in the alloy. In addition to the austenitic matrix, the electroslag ingot contains two types of carbides: M??C?, enriched with chromium (Cr), and M?C, enriched with Mo. After homogenization heat treatment at 1180?°C for 48?h, the coarse secondary phases were largely dissolved, and elemental segregation was significantly reduced. Consequently, the homogenized alloy exhibited excellent hot workability.