Ultrasonic constitutive model and its application in ultrasonic vibration-assisted milling Ti3Al intermetallics  

作　　者：Guofu GAO Zongxia FU Yi WANG Xianrong PAN Daohui XIANG Bo ZHAO 

机构地区：[1]School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo 454000,China

出　　处：《Chinese Journal of Aeronautics》2023年第7期226-243,共18页中国航空学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.51875179 and 52275419).

摘　　要：Ultrasonic vibration-assisted technology is widely utilized in the performance research and manufacturing process of metallic materials owing to its advantages of introducing highfrequency acoustic systems. However, the acoustic plasticity constitutive model and potential mechanism, involving Ti3Al intermetallic compounds, have not yet been clarified. Therefore, the Ultrasonic-K-M hybrid acoustic constitutive model of Ti3Al was established by considering the stress superposition, acoustic thermal softening, acoustic softening and acoustic residual hardening effects according to the dislocation density evolution theory and crystal plasticity theory. Meanwhile, the mechanical behavior of ultrasonic vibration-assisted tension(UVAT) and microstructure of ultrasonic vibration-assisted milling(UVAM) for Ti3Al was investigated. Dislocation density to be overcome from initial deformation to failure of Ti3Al was calculated in UVAT and was verified in UVAM. The results indicated that the Ultrasonic-K-M model showed a good agreement with the experimental data. There was an obviously softening phenomenon after introducing the ultrasonic energy field in the Ti3Al whole deformation region, and the degree of softening was positively correlated with amplitude. Furthermore, the maximum reduction ratio in yield strength of Ti3Al was16 % and the maximum reduction value in ultimate tensile strength was 206.91 MPa. The elongation rose first and then fell as amplitude enlarged, but only as the vibration was applied in the whole deformation region, the elongation was always greater than 14.58 %. In addition, The UVAM process significantly reduced the dislocation density increment to be overcome for Ti3Al material removal by 1.37 times, and promoted dislocation motion and cancellation to make twisted dislocations evolve into parallel dislocations. As the amplitude increased to 4 μm, the depth of the disturbed area of the plastic deformation layer increased by a maximum of 2.5 times.

关 键 词：Dislocation density Plastic deformation layer Ti3Al intermetallic compounds Ultrasonic-K-M hybrid acoustic constitutive model Ultrasonic vibration-assisted technology 

分 类 号：TG54[金属学及工艺—金属切削加工及机床]