Pressing the coarse-grained WC−10Co cemented carbide assisted by ultrasonic vibration

Abstract

The suppression technology assisted by longitudinal ultrasonic vibration was proposed to solve the problems of poor powder fluidity, uneven particle size distribution, and poor mechanical properties for the coarse-grained WC−10Co cemented carbides. The effects of compression force, height-diameter ratio, ultrasonic time of preloading, and ultrasonic amplitude on the compact density, compact surface quality, and mechanical properties of the alloys were discussed. The results show that, compared with the conventional pressing, the powder particles have the violent collision under the effect of ultrasonic vibration, enhancing the fluidity between particles. The density increases with the pressing force increase from 80 to 100 MPa. The compact density increases significantly, when the height-diameter ratio reduces, the ultrasonic time of preloading increases, and the ultrasonic amplitude increases. At the same time, the surface quality of the compacts is improved, and the elastic aftereffect is decreased by 0.16%. The pores of the alloys are reduced, the grain size is evenly distributed, and the coarse grain is reduced after sintering. With the little change in hardness and density, the fracture toughness increases by 5.83%~16.10%, while the bending strength decreases obviously.

Keywords

• cemented carbides
• ultrasonic vibration
• fluidity
• compact density
• mechanical properties