Accession Number : ADA086469


Title :   Structure and Deformation Characteristics of Rheocast Metals.


Descriptive Note : Final rept. 24 Jun 76-23 Jun 79,


Corporate Author : ILLINOIS UNIV AT URBANA-CHAMPAIGN DEPT OF METALLURGY AND MINING ENGINEERING


Personal Author(s) : Mehrabian,R ; Hosking,F M ; Portillo,F Folgar ; Wunderlin,R


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA086469


Report Date : Mar 1980


Pagination or Media Count : 95


Abstract : This report describes work aimed at developing wear resistant composites of aluminum base alloys, using Rheocasting and associated processes. It is anticipated that the feasibility of use of such composites in track blocks of land vehicles would be subsequently determined. Composites of two wrought (2014 and 2024) and one cast (201) aluminum alloys containing 2 to 30 weight percent of Al2O3 and SiC particles in the size range of the 1 to 142 micrometers were prepared using a compositing apparatus developed in this investigation. The non-metals were successfully added and retained in the aluminum alloy matrices using the rheological properties of a partially solidified, vigorously agitated alloy to advantage. Subsequently, the composites were reheated to above their liquidus temperature, shaped and solidified under high pressure in a forging press. The microstructures, the wear behavior and the mechanical properties of the composites were studied. Composites with particulate additions larger tham 5 micrometers in size possessed homogeneous structures. On the other hand, 1 micrometer particles tended to cluster. The wear behavior of the composites was studied on a pin-on-disk type machine built during this investigation. It was shown that composites containing large amounts of non-metals, about 20 wt%, of Al2O3 or SiC exhibit excellent wear resistance and low coefficients of friction. The wear mechanism in the matrices and the composites were also established.


Descriptors :   *ALUMINUM ALLOYS , *COMPOSITE MATERIALS , *ALUMINUM OXIDES , *RHEOLOGY , *CASTING , *SILICON CARBIDES , MICROSTRUCTURE , DEFORMATION , CARBIDES , MATRIX MATERIALS , CERAMIC MATERIALS , DUCTILITY , FRICTION , WEAR RESISTANCE


Subject Categories : Ceramics, Refractories and Glass
      Laminates and Composite Materials
      Fabrication Metallurgy
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE