电场活化烧结过程中升温速率对微型超声电机TC4锁套零件性能的影响

Effect of Heating Rates in Electric Field Activation Sintering Process on Performance of TC4 Lock Sleeve Used for Micro-Ultrasonic Motor

采用Gleeble-1500D热模拟机,研究了升温速率对微型超声电机TC4锁套零件性能的影响。应用阿基米德排水法测量试样的密度,使用扫描电镜(SEM)和高分辨透射电镜(HRTEM)检测零件的显微组织形貌。结果表明,在烧结温度为1000℃、升温速率50℃/s、压力75 MPa、保温时间240 s时试样的相对密度最高,可达95.4%,零件的相对密度随着升温速率的增大而提高。结合温度轴向收缩-时间曲线的特点,将烧结过程分为升温和保温两个阶段,其中升温阶段对零件致密化起主要作用。在多物理场的耦合作用下,颗粒的强塑性变形和纳米晶的生成是实现微型超声电机TC4锁套零件致密化的关键因素。

Using Gleeble-1500D thermal simulator,the effects of heating rates on the performance of TC4 microultrasonic motor lock sleeve were studied.The density of the sample was measured by Archimedes drainage method,and the microstructure of the part was detected by scanning electron microscope(SEM)and high resolution transmission electron microscope(HRTEM).The results show that the relative density of the sample is up to 95.4% when the sintering temperature is 1000℃,the heating rate is 50℃/s,the pressure is 75 MPa and the holding time is 240 s,and the relative density of the part increases with the increase of the heating rate.Combined the characteristic of temperature-time and axial direction-time,the sintering process is divided into two stages of temperature-raising and heat-preservation,the temperature-raising stage plays a major role in the densification of the part.Under the coupling of multiple physical fields,the severe plastic deformation of the particles and the formation of nanocrystalline are critical factors which realize the densification process of the TC4 micro ultrasonic motor lock sleeve.