材料期刊网

Hydrostatic extrusion of a Zr(38)Ti(17)Co(10.5)Co(12)Be(22.5) bulk metallic glass/porous tungsten phase composite was perform ed, and the dynamic compressive deformation and fracture behavior of the as-extruded composite we. re investigated in detail at room temperature by means of the Split Hopkinson Pressure Bar (SHPB). In comparison with the as-cast composite, the as-extruded composite presented a much higher flow stress without sacrificing plasticity under dynamic compression,. exhibiting ductility increment, but evidence of work softening was observed. The specimen for the as-extruded composite failed by axial splitting with occasional shear fracture in some regions. It is suggested that the increase in flow stress and ductility of the as-extruded composite is attributed to the extrusion process which introduced hardened condition and texture in the tungsten phase as well as the 3D net structure of the porous tungsten phase. The work softening mechanism, Wears to be essentially associated with the large number of microcracks and voids under dynamic compression. (C) 2008 Elsevier Ltd. All rights reserved.