NUMERICAL-SIMULATION OF THIXOFORMING

Processing of alloys and composites in the solid plus liquid range has advantages over casting, forging, and powder metallurgy techniques, T he sensitivity of semisolid slurries to temperature variations and the ir history and rate dependent behavior, however, make process design a nd control difficult, Precise selection of die velocity, process tempe rature, and die design is necessary to produce satisfactory products. Therefore, a computational capability for the prediction of the theolo gical behavior of semisolid materials would be an invaluable tool in p rocess design, This work presents preliminary results on numerical sim ulations of thixoforming operations. Constitutive models that are able to describe qualitatively the transient flow behavior of semisolid ma terials are implemented in a finite element program. Simple but realis tic thixoforming operations are simulated, Weaknesses of currently ava ilable constitutive models and numerical techniques are identified and discussed.