MODELING EXTRUSION OF 2618-ALUMINUM-ALLOY AND 2618-10-PERCENT-AL2O3 AND 2618-20-PERCENT-AL2O3 COMPOSITES

The metal matrix composites 2618-10%Al2O3 and 2618-20%Al2O3 have been subjected to hot torsion tests for temperatures T from 300 to 500 degr ees C and strain rates (epsilon) over dot from 0.1 to 5 s(-1). The flo w stresses decrease with? increasing temperature and decreasing strain rate and the composites have greater strength than the matrix alloy.. The strength of the extruded 2618-10%Al2O3 is higher than that of the as cast 2618-20%Al2O3. A constitutive analysis has been carried out w ith the sinh Arrhenius equation for the composites and the alloy. Plot s of log (epsilon) over dot versus log(sinh alpha sigma(p)) and log(si nh alpha sigma(p)) versus 1/T ni e approximately linens over the range of conditions tested. To improve the deformation processing, which is required for. many discontinuously reinforced metal matrix composites , the extrusion of the three materials has been modelled using the fin ite element software Deform and the constitutive laws determined above . Of particular significance al e the dependences of peak load and max imum temperature on biller temperature and rain speed for an extrusion ratio of 31. MST/4021A.