Microstructure and tribological properties of in-situ formed Al3Zr/A356 composite

Abstract

Abstract A13Zr/A356 Composite was prepared by in-situ reaction of K2ZrF6 powder and cast aluminum A356 melt at different temperatures (710 °C, 750 °C, 770 °C, 790 °C). The effect of different melting temperature on the morphology of Al3Zr particles was studied, and the sliding friction and wear properties of the composites were studied by wear test. It can be seen from the x-ray diffractometer (XRD) that the prepared composite material consists of A13Zr and ɑ-Al, and also has a small part of the aluminum-silicon eutectic phase; SEM analysis shows that the particles of in-situ reinforced phase are fine, With the increase of temperature, the morphology of A13Zr reinforced phase changed from block to needle and strip, and the particle distribution of the reinforced phase was uniform and well dispersed in the matrix at 750 °C. TEM experiments show that the reinforced phase exists at 750 °C and has a good combination with the matrix, which plays a very good role in particle reinforcement Friction and wear experiments show that the different preparation temperature results in different phase morphology. The reinforced phase particles existing on the surface of composites at 710 °C and 750 °C bear most of the friction, so the friction coefficient of the composites is larger at these preparation temperature, and the main wear modes are oxidation wear and abrasive wear. The friction coefficient of the composites prepared at 770 °C and 790 °C is small, and the wear modes are mainly delamination wear and oxidation wear. When the preparation temperature is 750 °C, the wear resistance of the composites is the best.