Investigation on crack of Mg-Li alloy during laser rapid prototyping

Through mathematical analysis and simulation, the mechanical properties of Mg-Li alloy by laser rapid prototyping (LRP) and prototyping mechanism on cracks have been investigated. Mg-Li alloy with deposition phase is of higher strength, lower ductility and more distinct anisotropy and LRP defect is studied using microscopic analysis methods. The spherical porosity is randomly distributed in Mg-Li alloy samples because of loose powders and irregular ill bonding. The investigation results show that the cladding cracks are formed in grain boundary with dendrite structure commonly and presented as characteristics of cracking along grains. It is concluded that the liquefying cracks are with cracking characteristics along grains and the pre-layer is pulled apart by the increasing residual tensile stress in the laser deposition process and the cracks enlarged generally along the central line of the overlapping zone.