Controlled Diffusion Solidification (CDS) of Al-Zn-Mg-Cu (7050): Microstructure, heat treatment and mechanical properties

Abstract

The tilt pour gravity casting process coupled with the Controlled Diffusion Solidification (CDS) process technology was employed to demonstrate the ability to cast AA7050 wrought alloy into high integrity near net shaped components with high strength and ductility. The CDS technology involves mixing two precursor alloys at different thermal mass and subsequently casting the resultant mixture into near net shaped cast components. The process enables casting of the high performance Al wrought alloys into near net shaped components by circumventing the problem of hot tearing by obtaining a non-dendritic morphology of the primary Al phase. This study presents the process and alloy parameters necessary for the casting of 7050 Al wrought alloy (Al-Zn-Mg-Cu) using the CDS process technology. The uniaxial tensile properties after various heat treatment conditions such as as-cast, solutionizing and annealing mandatory to the development of the artificial ageing were investigated and presented along with in-depth and quantitative microstructural analyses.