摘要
钛合金在航空领域中的应用越来越广泛。为了优化钛合金激光切割工艺,针对广泛使用的4 mm厚的退火态(M态)TC4钛合金,选取了激光功率、离焦量、切割速度和辅助气体压力四个工艺参数,设计了单因素试验和四因素五水平正交的激光切割试验,基于切缝宽度、挂渣高度和异常组织区宽度三个质量评价指标,研究了工艺参数对切割质量的影响规律,并建立回归方程,预测和验证了最优切割工艺参数。试验结果表明,对切缝宽度影响最显著的工艺参数为激光功率和离焦量,对挂渣高度影响最显著的参数为气体压力和激光功率,对异常组织区宽度影响最显著的因素是切割速度和离焦量,建立的回归方程预测结果与验证试验结果吻合较好。
Objective Titanium alloys are extensively used in the primary bearing structures of highperformance aircraft owing to their high specific strength,excellent corrosion resistance,and superior fatigue strength.Among these,the Ti6Al4V(TC4)titanium alloy is the most commonly used in aerospace applications.However,because of its low thermal conductivity and tendency to adhere to cutting tools,its machinability is relatively poor,resulting in high manufacturing costs.This severely limits the application of titanium alloys in the aerospace sector.Laser cutting offers several advantages over traditional methods,including a smaller heataffected zone,reduced thermal deformation of the workpiece,and higher processing efficiency.However,the complexity of the cutting process parameters makes systematic testing essential for parameter optimization to achieve high cutting quality.Given the widespread use of mediumthickness titanium plates in aircraft primary bearing structures,conducting indepth studies on the optimization of the laser cutting process is important.Methods Aiming at the laser cutting of 4 mm thick TC4 titanium alloy plates,a onefactor test is designed to select the key process parameters of laser power,defocusing amount,cutting speed,and auxiliary gas pressure,thereby studying the influence law and mechanism on cutting quality,such as kerf width,slaghanging height,and abnormal tissue zone width.The kerf width and abnormal tissue zones are observed and measured using a metallurgical microscope,whereas the cut surface morphology and slaghanging height are examined using a body microscope.Variations in hardness in the abnormal tissue zones are measured using a microhardness tester.Orthogonal tests are designed,and analysis of variance(ANOVA)and multiple regression methods are applied to analyze the effect of each process parameter.Prediction models for each quality evaluation index are developed;process parameters are optimized;and the accuracy of the prediction models is validated through experiments.Results and Discussions In studying the process parameter effects on cutting quality,when nitrogen is used as an assistive gas,the cut surface appears greyishblack(Fig.8).From top to bottom,the surface is divided into three zones:smooth,rough,and slaghanging(Fig.9).The variation in the width of the smooth zone is primarily due to the combined effects of heat input and melt blowing(Fig.11).After laser cutting,the remelted and heataffected zones and the matrix show a significant decrease in microhardness,primarily because of the martensitic phase transformation at the slit edge(Fig.12).The optimal process parameters for the narrowest cutting slit,as predicted by the regression equation fitted through response surface analysis(Table 6),are:laser cutting power of 2563 W,defocusing amount of-4 mm,cutting speed of 0.06 m/s,and gas pressure of 1.1 MPa.The optimal parameters for minimizing slaghanging height are:laser power of 3060 W,defocusing amount of-5 mm,cutting speed of 0.12 m/s,and gas pressure of 1.8 MPa.The optimal parameters for minimizing the abnormal tissue zone are:laser power of 3091 W,defocusing amount of-5 mm,cutting speed of 0.12 m/s,and gas pressure of 1.7 MPa.Conclusions The test results indicate that the process parameters that most significantly affect the kerf width are laser power and defocusing amount,whereas gas pressure and laser power have the greatest influence on the slag hanging height.Cutting speed and defocusing amount are the factors most affecting the abnormal tissue zone.Based on the orthogonal test results,a regression model is developed for the kerf width,abnormal tissue zone width,and slaghanging height,to accurately predict the optimal cutting quality process parameters.The resulting optimal parameter combinations lead to the narrowest kerf width of 0.214 mm,smallest slaghanging height of 0.017 mm,and smallest abnormal tissue zone width of 180.88μm.These findings provide valuable guidance for improving the laser cutting quality of mediumthickness titanium alloys.
作者
张雅
徐文涛
王春雨
张献逢
卿华
谈敦铭
王帅
Zhang Ya;Xu Wentao;Wang Chunyu;Zhang Xianfeng;Qing Hua;Tan Dunming;Wang Shuai(School of Mechanics and Safety Engineering,Zhengzhou University,Zhengzhou 450001,Henan,China;Aviation Maintenance NCO Academy,Air Force Engineering University,Xinyang 464001,Henan,China;School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,Guangxi,China)
出处
《中国激光》
北大核心
2025年第8期12-27,共16页
Chinese Journal of Lasers
基金
国家自然科学基金(12102396)。
关键词
激光技术
激光切割
钛合金
工艺参数
显微组织
laser technique
laser cutting
titanium alloy
process parameter
microstructure
