摘要
基于侧吹保护条件下的光纤激光非穿透深熔焊接工艺,模拟了构件的服役环境,对GH3128搭接接头进行了不同循环次数的900℃真空热处理,并对接头组织和显微硬度、室温与高温拉伸及蠕变拉伸性能进行了分析测试,通过分析组织与断口,对GH3128搭接接头的高温力学性能进行了评估。研究结果表明,与无热处理接头相比,热处理后的接头的室温与高温拉伸性能分别提升了35%和20%,蠕变性能大幅提高。接头组织分析结果表明:热处理后的接头枝状组织消熔,晶粒呈粗大等轴晶状态;各断口均呈现出“抛物线”状韧窝,开口方向与拉伸力方向一致,呈韧性断裂特征,且无显微裂纹产生;热处理次数对接头显微硬度、室温及高温拉伸性能的影响不大;随着热处理次数的增加,接头蠕变性能呈减小趋势。
Objective GH3128 has the benefits of strong heat, pressure, and corrosion resistance, and is extensively employed in high-temperature components of active thermal protection structures in the aerospace field. Laser welding is the primary manufacturing process of active thermal protection components, and the lap joint is the primary joint form. The thermal load condition of the active thermal protection components is harsh, which puts forward higher demands on the hightemperature mechanical properties of lap joints. In this study, in view of the joint forms and high-temperature short-time work characteristics of active thermal protection components, the microstructure and mechanical properties of GH3128 lap joints under different vacuum heat treatment conditions are investigated on the basis of fiber laser non-penetrating deep fusion welding process under the condition of side blowing protection.Methods The test materials are GH3128 plates with the solution state, the upper plates’ size is 200 mm×150 mm×1 mm, and the lower plates’ size is 200 mm×150 mm×2 mm. The light source is a fiber laser with a wavelength of 1060--1070 nm. The beam focusing parameter is Kf=8 mm. mrad, the transmission fiber core diameter is 200 μm, the output coupling collimator’s focal length is 200 mm, and the focusing lens’ focal length is 300 mm. High purity Ar gas is employed as the protection gas, and the flow rate is 8 L/min. The nozzle’s inner diameter is 8 mm, the phosgene spacing is 2 mm, the nozzle’s output length is 6 mm, and the protective gas output angle is 50°. The welding process parameters are as follows: the laser output power is 1500 W, the welding speed is 2 m/min, and the defocusing is 0. After welding, the mechanical properties of GH3128 lap joints are tested, and the GH3128 lap joints are subjected to 900 ℃ vacuum heat treatment with different cycles. The weld is corroded with aqua regia(6 m LHCl+2 m LHNO 3), cleaned with alcohol, and used as a metallographic sample. An optical microscope is employed
作者
袁振飞
蒋劲
程智伟
杜欣
祁百鑫
武强
杨顺华
肖荣诗
Yuan Zhenfei;Jiang Jin;Cheng Zhiwei;Du Xin;Qi Baixin;Wu Qiang;Yang Shunhua;Xiao Rongshi(High-Power and Ultrafast Laser Manufacturing Laboratory,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;Science and Technology on Scramjet Laboratory,China Aerodynamics Research and Development Center,Mianyang 621000,Sichuan,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第21期164-172,共9页
Chinese Journal of Lasers
基金
国家自然科学基金面上项目(51775009)
高超声速冲压发动机技术重点实验室开放课题(STSMY-KFKT-2020003)。
