热挤压模具用钴基合金微观组织及高温摩擦磨损性能研究

Research on microstructure and high temperature friction and wear properties of cobalt based alloy for hot extrusion die

热挤压模具是决定挤压制品表面质量和尺寸精度的关键工具,其服役过程承受高温、高压、磨损等作用,因此要求具有较高的高温摩擦磨损性能。研究了钴(Co)基合金的高温摩擦磨损性能,并与热挤压模具原材质碳化钛(TiC)金属陶瓷的高温摩擦磨损性能进行对比分析和机理研究。研究结果表明,Co基合金高温磨损性能优于TiC金属陶瓷高温磨损性能,并具有代替TiC金属陶瓷作为热挤压模具材料的可行性。Co基合金高温磨损性能优于TiC金属陶瓷高温磨损性能,主要是由于Co基合金致密度高,基体与碳化物的结合好,在磨损过程中碳化物不易从基体剥落,同时,冲击韧性较好,不易产生微裂纹并导致磨损表面剥落的发生。

Hot extrusion die is the key tool determining the surface quality and dimensional accuracy of extruded products.Its service process is subject to high temperature,high pressure and wear,so it requires high friction and wear properties.The high-temperature friction and wear properties of cobalt(Co)-based alloys were investigated,and compared with that of the titanium carbide(TiC)cermet.The results showed that the high-temperature wear performance of Co-based alloy was better than that of TiC cermet,and it had the feasibility of replacing TiC cermet as hot extrusion die material.Due to the high density and good combination of matrix and carbide,the carbides were not easily peeled off from the matrix during wear process.Meanwhile,It was not easy to generate microcracks on Co-based alloys,causing the occurrence of worn surface peeling because of the higher impact toughness.As a result,the high temperature wear performance of Co-based alloys is better than that of TiC cermet.