The influence of stress and strain on the solid/liquid segregation formed in deformed semisolid metal was studied.Thecompression experiment at a low constant strain rate was conducted on a Gleeble 1500 thermo-mechanic...The influence of stress and strain on the solid/liquid segregation formed in deformed semisolid metal was studied.Thecompression experiment at a low constant strain rate was conducted on a Gleeble 1500 thermo-mechanical sireulator.The stress and strain fields of the samples were calculated by finite element method.The experiment results and themodeling results prove that the hydrostatic pressure gradient is the driving force for solid/liquid segregation.Thesegregated liquid phase usually agglomerates in the micropores and shear bands are created by sliding of equiaxeddendrite grains.The sliding among the grains is influenced by the solid fraction and grain size of the semisolid slurry,so as the solid fraction and grain size change,the morphology of the segregated liquid changes.展开更多
The mechanical behavior of LC 4 alloy in the semisolid state at high volume fractions of solid has been studied through unconstrictive compressing test. The results show that peak stress mainly depends on grain bound...The mechanical behavior of LC 4 alloy in the semisolid state at high volume fractions of solid has been studied through unconstrictive compressing test. The results show that peak stress mainly depends on grain boundary’s cohesion and instantaneous strain rate sensitivity in the semisolid state, which is similar to that in the solid state. Analyses on microstructures and status of compressive stress of specimen demonstrate that segregation of liquid solid phase is mainly affected by strain rate and deformation temperature. There are mainly two kinds of flow in liquid phase: either from the region with relatively large hydrostatic compressive stress to the region with relatively small hydrostatic compressive stress or from the grain boundaries perpendicular to the compression axis to the grain boundaries with a certain directional angle to the compression direction. Based on the above results, compressive deformation mechanism mainly depends on deformation temperature, strain rate and stress state.展开更多
文摘The influence of stress and strain on the solid/liquid segregation formed in deformed semisolid metal was studied.Thecompression experiment at a low constant strain rate was conducted on a Gleeble 1500 thermo-mechanical sireulator.The stress and strain fields of the samples were calculated by finite element method.The experiment results and themodeling results prove that the hydrostatic pressure gradient is the driving force for solid/liquid segregation.Thesegregated liquid phase usually agglomerates in the micropores and shear bands are created by sliding of equiaxeddendrite grains.The sliding among the grains is influenced by the solid fraction and grain size of the semisolid slurry,so as the solid fraction and grain size change,the morphology of the segregated liquid changes.
文摘The mechanical behavior of LC 4 alloy in the semisolid state at high volume fractions of solid has been studied through unconstrictive compressing test. The results show that peak stress mainly depends on grain boundary’s cohesion and instantaneous strain rate sensitivity in the semisolid state, which is similar to that in the solid state. Analyses on microstructures and status of compressive stress of specimen demonstrate that segregation of liquid solid phase is mainly affected by strain rate and deformation temperature. There are mainly two kinds of flow in liquid phase: either from the region with relatively large hydrostatic compressive stress to the region with relatively small hydrostatic compressive stress or from the grain boundaries perpendicular to the compression axis to the grain boundaries with a certain directional angle to the compression direction. Based on the above results, compressive deformation mechanism mainly depends on deformation temperature, strain rate and stress state.
