Microstructure Transformation and Refinement Mechanism of Undercooled Cu-Ni-Co Alloy Based on Simulation of Critical Cutting Speed in Ultrasonic Machining  

作　　者：HE Xiaoyu HOU Kai XU Xuguang TANG Cheng ZHU Xijing 

机构地区：[1]School of Mechanical Engineering,North University of China,Taiyuan 030051,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2023年第6期1472-1483,共12页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the Basic Research Projects in Shanxi Province(202103021224183)。

摘　　要：Both Cu60Ni38Co2 and Cu60Ni40 alloy were naturally cooled after rapid solidification from the liquid phase.The transformation law of the microstructure characteristics of the rapidly solidified alloy with the change of undercooling(ΔT)was systematically studied.It is found that the two alloys experience the same transformation process.The refinement structures under different undercoolings were characterized by electron backscatter diffraction(EBSD).The results show that the characteristics of the refinement structure of the two alloys with low undercooling are the same,but the characteristics of the refinement structure with high undercooling are opposite.The transmission electron microscopy(TEM)results of Cu60Ni38Co2 alloy show that the dislocation network density of low undercooled microstructure is lower than that of high undercooled microstructure.By combining EBSD and TEM,it could be confirmed that the dendrite remelting fracture is the reason for the refinement of the low undercooled structure,while the high undercooled structure is refined due to recrystallization.On this basis,in the processing of copper base alloys,there will be serious work hardening phenomenon and machining hard problem of consciousness problems caused by excessive cutting force.A twodimensional orthogonal turning finite element model was established using ABAQUS software to analyze the changes in cutting speed and tool trajectory in copper based alloy ultrasonic elliptical vibration turning.The results show that in copper based alloy ultrasonic elliptical vibration turning,cutting process parameters have a significant impact on cutting force.Choosing reasonable process parameters can effectively reduce cutting force and improve machining quality.

关 键 词：rapid solidification UNDERCOOLING microstructure refinement structure ultrasonic elliptical vibration turning cutting speed finite element analysis 

分 类 号：TG506[金属学及工艺—金属切削加工及机床]