Commonly investigated problem on composite fabrication and forming for weight reduction in transportation and aerospace area is not completely cleared. The main difficulties on composites forming without building any defects caused new ways on process characterization due to the key parameters. In the paper two main problems were investigated, i.e. material fracture and material thinning during deep drawing. Through mechanical tests and numerical simulation the authors tried to couple the fracture with the technological boundary conditions of the deep drawing process and form a housing test part from a three-layer material.

Specimens of the Al — 15% Ca alloy comprising more than 55% of the Al4Ca intermetallic compound were subjected to hot and cold stamping with torsion. Alloys with a high concentration of intermetallic compounds can be used as materials with a low thermal expansion ratio. Stamping with torsion creates severe shear strains. The material structure sees quality changes in the tangential direction, and a fine-grained structure is formed, which enhances the mechanical and physical properties of the material. The equipment used in this research is capable of producing large workpieces with diameters reaching 150 mm. An electric resistance furnace was used to produce the experimental alloy. For better ductility, the cast specimens were annealed at 550 оС in a laboratory furnace. Such annealing procedure results in fragmented eutectic intermetallic compounds which then become of a round shape. For hot stamping with torsion, the stamp was heated to 450 оС, while the temperature of the workpiece was raised to 500 оС; pressure applied – 1 MN; die rotation – 180 degrees. No heat was applied to either the stamp or the workpiece during cold stamping, the same pressure and die rotation were applied as during hot stamping. The microstructure of the primary cast specimens contains aluminium-calcium eutectics, as well as primary crystals of the Al4Ca intermetallic compound of a round or platelet shape. Multiple pores are also present in them. The microstructure of the specimens after hot and cold stamping with torsion is quite non-homogenous. Compared with the peripheral areas, the centre of the specimens has a more consistent structure, finer intermetallic particles, and a higher hardness. The resultant specimens have almost no pores, the primary intermetallic compounds are fragmented and evenly distributed in the specimens, and the hardness rises almost twice compared with the as-cast state.This research was funded by the grant 14-19-00632P (metallographic study) of the Russian Science Foundation and under the Assignment No. 11.2072.2017/4.6 (experimental stamping with torsion).