Deformation behavior of steels in mushy state

Processing metals in a semisolid or mushy state has emerged as a vital commercial process to produce metal and metal-matrix composite components. The understanding of the basic deformation behavior of materials in the mushy state is critical for better control of various semisolid processes. The aim of the present study is to quantify the flow stress of mushy-state steels under uniaxial deformation conditions. A hot compression tester has been developed to provide the high temperature setting required for testing mushy-state steels. An analytical scheme, which only requires measuring the dimensions of the final solidified specimen, has been developed to eliminate the barreling effects occurring in compression tests. The temperature of specimens has been carefully controlled to correlate the solid phase content. It has been found that the flow stress of steels in mushy states was highly dependent on the solid phase percentage. The relaxation of steel and stress reduction at mushy states is also discussed.