AI-SiC INTERFACE STRUCTURE STUDIED BY HREM

Abetract--A comparison is made between the two well-known aluminium alloys 2014 and 6061, cold pressed from powder and subsequently extruded, with and without a reinforcement of 30 wt% •-SiC particulates. The former one has a strength of 550 MPa and a strain at fracture of 1 % while the latter one has a more moderate strength of 415 MPa but a fracture strain of 4%. A high resolution electron microscopy study of the AI-SiC interface indicates that proper wetting is achieved in both alloys. A preferred orientation relationship s observed in the 6061-SIC combination: (0001)mc//{111}~; (2IT0)sc//(110)~. When the (0001)~c is not parallel to the interface, a stepped interface is observed with the 6061 alloy, with one part of the step parallel to the SiC basal plane and one type of the AI octahedral p anes and the other part parallel to another type of AI octahedral p anes. In the 2014 alloy the steps eem to be less pronounced probably due the processing route. effectue une comparaison entre deux alliages d'aluminium bien conntm 2014 et 6061 comprim6s ~ froid ~ partlr de poudres, puis extrudes avec ou sans renfort de 30 % en poids de particules de SiC-or. Le premier a une r6sistance mb~mique d 550 MPa et une d6formation A la rupture de 1 % tandis que le second a une r~stauee mbvanique plus m ~ de 415MPA, mais une dfformation ~ la rupture de 4%. Uue 6tude par microscopic 61ectronique enhante r~olution d