The Study On Aluminum Matrix Composites Reinforced By In-Situ Rare-Earth Compounds Fabricated By Modification

ZL108 alloy is the common alloy used in engine piston. Because its small density, low thermal dilation coefficient and excellent wearablity open out favorable foreground. Aluminium piston is heart of the engine, which quality mostly influence the properties of the engine. ZL108 alloy was used to cast aluminium piston ever, which has excellent foundry performance and mechanical properities, but the constant development of automobile engine towards high speed and high pressure leads to higher and higher demands for properties of engine piston. So it is necessary to further research how to increase the mechanical capability especially high temperature performance.The lanthanide can effectively modify the morphology of eutectic Si phase in aluminium alloys and have long effect, which enhance mechanical capability of the alloy greatly. The Al-Si alloy piston which modified by lanthanide not only has well room temperature performance, but also increases high temperature of the alloy. Al-Re alloy was rapidy solidificated, so its microstructure was turned into amorphous state, nanocrystal or minicrystal. Adding the rapidly solidificated Al-Re alloy into task alloy ,the high temperature properties of Al alloy as-cast could be increased the effectively.Modified by Melt Rapid Solidification (MRS) Al-Re (Ce, La) inoculant alloy, the microstructure of the modified ZL108 alloy was observed by using SEM, and properties was compared. The results show that the microstructure of the modified alloy is refined, and the mechanical properties are much better than that of modified by traditional Al-Re (Ce, La) massive inoculant alloy. Therefore, the MRS Al-Re (Ce, La) modification could improve greatly the performances of ZL108 alloy.The function of lanthanide in ZL108 alloy were studied by using SEM, EDAX and tensile and wearing tests. It shows that adding to lanthanide not only reduce ZL108 alloy casting porosity greatly, but also modificate secondry phase. It makes the secondry phase from skeleton to fine. New type heat-resistant aluminium alloy was modified by using MRS Al- La, MRS Al-Ti-B and MRS Cu-P Multiplex modificator, then the microstructure of the new type heat-resistant aluminium alloy was observed and its properties was tested. The results indicate that the microstructure of Al alloy modified by new inoculant are much better than that of modified by traditional Al- La ,Al-Ti-B, Cu-P multiplex modificator.