摘要:
本文采用粉末冶金热等静压工艺制备了Inconel 718合金锭，对Inconel 718合金锭进行三种不同制度的热处理，分别为固溶（980 ℃保温1 h后水淬）+时效（780 ℃保温8 h后空冷）、固溶（1020 ℃保温1 h后水淬）+时效（780 ℃保温8 h后空冷）、固溶（1020 ℃保温1 h后水淬）+时效（720 ℃保温8 h后空冷）。采用光镜、X射线衍射仪、扫描电镜、透射电镜等仪器设备对热处理前后的Inconel 718合金锭进行微观组织及力学性能分析。结果表明：HIP态Inconel 718合金锭强度与锻件相当，由于原始粉末颗粒边界（prior particle boundaries，PPBs）的存在降低了材料HIP态Inconel 718合金的塑性，故塑性略低于锻件的塑性。固溶处理后，PPBs部分被消除，从而改善了材料的塑性。随着时效温度的升高，γ''/γ'相过度时效，材料强度降低，塑性提高。最优的热处理工艺为固溶（1020 ℃保温1 h后水淬）+时效（780 ℃保温8 h后空冷）。
Abstract:
The Inconel 718 alloys were prepared by the power metallurgy hot isostatic pressing (PM-HIP). The obtained alloy ingots were subjected to heat treatments under three different parameters, holding at 980℃ for 1 hour followed by water quenching, then holding at 780℃ for 8 hours followed by air cooling, holding at 1020℃ for 1 hour followed by water quenching, then holding at 720℃ for 8 hours followed by air cooling, holding at 1080℃ for 1 hour followed by water quenching, then holding at 780℃ for 8 hours followed by air cooling, respectively. Tensile strength and microstructure of as-HIPed alloy were characterized via the Optical Microscope (OM), X-ray diffractometer (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM) et al. Results indicated that: the tensile strength of as- HIPed Inconel 718 alloy at room temperature is equivalent to that of forged parts, while the ductility is lower than that of the as-forged parts owing to the presence of prior particle boundaries (PPBs). Part of PPBs were eliminated during the solution treatment, thus the ductility of the as-HIPed alloy was improves. As the aging temperature increased, the γ''/γ' phases were over-aged, the strength of the material decreased and the ductility increased. The optimized heat treatment process was as follows: holding at 1020℃ for 1 hour followed by water quenching, then holding at 780℃ for 8 hours followed by air cooling.
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