Tensile Deformation Behavior of a Directionally Solidified Superalloy in the Range from Cryogenic Temperature to High Temperature

Abstract

The tensile deformation behavior of directionally solidified superalloy DZ406 was investigated at cryogenic temperatures from -\(125^{\circ}\)C to \(25^{\circ}\)C, and the comparative analysis of room temperature and \(1000^{\circ}\)C was carried out. The yield strength and ultimate strength at cryogenic temperatures were close to that at room temperature, and twice that at \(1000^{\circ}\)C. The elongation was maintained at 10–15% and exhibited a certain plasticity at cryogenic temperatures. At cryogenic temperatures, the fracture samples essentially showed no necking phenomenon, and the cracks primarily occurred in the MC carbide itself in the interdendritic areas. At room temperature and \(1000^{\circ}\)C, however, the fracture surface was covered in dimples that contained carbides. At cryogenic temperatures and room temperature, slip bands and dislocations both contributed to the tensile deformation; however, at \(1000^{\circ}\)C, only the dislocations were active.