MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SEMI-SOLID EXTRUDED IN-SITU Al-4.5Cu-0.8Mg/TiCp COMPOSITES

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＳＥＭＩＳＯＬＩＤＥＸＴＲＵＤＥＤＩＮＳＩＴＵＡｌ４．５Ｃｕ０．８Ｍｇ／ＴｉＣｐＣＯＭＰＯＳＩＴＥＳ①ＺｈａｎｇＥｒｌｉｎ，ＹａｎｇＢｏａｎｄＺｅｎｇＳｏｎｇｙａ...

A novel in situ approach was used to prepare titanium carbide(TiC) reinforced Al based composites. The reacted, semi solid extruded samples exhibited a homogeneous distribution of fine (0.1～1 um) TiC particles in a fine grained Al 4.5Cu 0.8Mg matrix. The microstructures observed by TEM show that no reacted products were found in the interfaces between the matrix and the TiC particles, displaying that the interface cohesion strength is strong. The testing results have also shown that σ y and σ b of the composites have been improved greatly, which are about 439 MPa and 549 MPa, increasing by 55% and 29%, respectively, compared with those of unreinforced alloy. The fracture morphologies observed by SEM show that they belong to a micro ductility fracture, and that existence of coarse Al 3Ti and segregation of TiC particles are also the causes of fracture.