长期时效对GH3625合金热挤压管组织及性能的影响  

Effects of Longterm Aging on Microstructure and Mechanical Properties of Hot-extruded GH3625 Alloy Tube

作　　者：丁雨田[1] 豆正义 高钰璧 高鑫[1] 

机构地区：[1]兰州理工大学材料科学与工程学院省部共建有色金属先进加工与再利用国家重点实验室

出　　处：《特种铸造及有色合金》2017年第4期373-377,共5页Special Casting & Nonferrous Alloys

基　　金：甘肃省重大科技专项资助项目(145RTSA004);国家自然科学基金资助项目(51661019)

摘　　要：采用SEM、EDS分析,Image-Pro plus金相分析软件等手段,研究了720℃时不同时效时间对GH3625合金热挤压管材组织和性能的影响。结果发现,挤压态GH3625合金在720℃长期时效后主要析出M23C6、γ"相和δ相,合金的强度和硬度均提高,塑性显著下降。随着时效时间延长,部分M23C6转变为M6C,大部分γ"相转变为针状δ相,时效5 000h后δ相由长针状变为长棒状,减弱了γ"相对合金的强化作用;δ相随着时效时间的延长发生长大,平均生长速率为5.9×10~8nm^3/h,遵循LSW理论,而平均宽度的粗化却偏离了LSW理论。The effects of different aging time on microstructure and properties of hot-extruded GH3625 alloy tube at 720 ℃ were investigated by means of scanning electron microscopy （SEM）, energy-dispersive spectrometry（EDS） and Image-Pro plus metallographic analysis software. The results indicate that the M23 C6, γ＂ phase and δ phase are mainly precipitated in the GH3625 alloy at 720 ℃ during long term aging, and the strength and hardness of GH3625 alloy are increased, however, the plasticity is decreased drastically. With the increase of aging time, some M23 C6 phases are transformed into M6C, and most of the γ＂ phases are transformed into acicular 3 phase. In addition, after aging for 5 000 h, the δ phase is changed from long acicular to long rod-like, weakening strengthening effect of γ＂ phase. The δ phase is grown up with aging time and the average growth rate length 5.9 × 108 nm3/h, following LSW theory, while the average width of coarsening is deviated from the LSW theory.

关 键 词：GH3625合金 长期时效 Δ相 LSW理论 

分 类 号：TG132.3[一般工业技术—材料科学与工程]