NUMERICAL-SIMULATION OF THIXOFORMING

Processing of alloys and composites in the solid plus liquid range has advantages over casting, forging, and powder metallurgy techniques, The sensitivity of semisolid slurries to temperature variations and their history and rate dependent behavior, however, make process design and control difficult, Precise selection of die velocity, process temperature, and die design is necessary to produce satisfactory products. Therefore, a computational capability for the prediction of the theological behavior of semisolid materials would be an invaluable tool in process design, This work presents preliminary results on numerical simulations of thixoforming operations. Constitutive models that are able to describe qualitatively the transient flow behavior of semisolid materials are implemented in a finite element program. Simple but realistic thixoforming operations are simulated, Weaknesses of currently available constitutive models and numerical techniques are identified and discussed.