Generally speaking, metal materials have good toughness but poor wear resistance. Ceramic materials have good wear resistance but poor toughness. Therefore, the composite of ceramics and metals can effectively combine both advantages to obtain metal-ceramic composite materials that are both strong and wear-resistant.

Professor Chen Hongsheng of Taiyuan University of Technology and his collaborators used AlCoCrFeNi2.1 high entropy alloy as the matrix and tungsten carbide as the reinforcement phase. Using the Fast Hot Pressing Sintering technology to prepare Metal-ceramic composites. The experiment found that this technology can achieve rapid densification of composite materials. And minimize the degradation of composite material performance.

Experimental process

The experimental process studied the materials’ composition phases and composite interfaces and analyzed their interface behavior during sintering. Perform the Micro-nano hardness tests and friction and wear tests. Analyze the friction properties. And discuss the tribological behavior and wear mechanism of WC/AlCoCrFeNi2.1 HEAs composites. The relevant results were published in the journal Tribology International.

In the experiment, mix the finished high entropy alloy powder and tungsten carbide powder by ball milling and then loaded into a graphite mold. Using our CNE-FHP-808 Fast Hot Pressing Sintering furnace to sinter the material. The sintering pressure was 50MPa, the heating rate was 100℃/min. The sintering temperature was from 950℃ to 1050℃, and the holding time was 5 minutes. The entire sintering process is under vacuum conditions. The obtained samples had good density, and the elements in the high entropy alloy were evenly distributed in the samples.

Experimental results

Evaluate the friction performance of the material by a friction and wear tester, the friction ball is alumina. Subsequently, analysis of the friction surface microstructure observation and composition using a scanning electron microscope combined with an energy spectrometer. The friction and wear mechanism was discussed.

The following phenomena can be found through systematic microstructure analysis and friction and wear tests. The HEAs matrix in the composite material has a dual-phase eutectic structure of FCC and BCC phases. The interface layer is mainly M7C3 and M23C6 (M=Cr, W). The microhardness and wear resistance of the composite material increase proportionally with the increase of the reinforcement phase particles. During the friction process, the oxide film formed on the surface of the material provides additional protection, enhances stability, and reduces the losses caused by friction. The main types of wear are adhesive wear, abrasive wear, and three-body wear.