Direct Laser Metal Deposition of Al 7050 Alloy

Additive manufacturing (AM) of metals is finding numerous applications in automotive industry. In 21^st century, aluminum is second to steel in automotive sector, because of its high strength to weight ratio. Hence developing AM for aluminum alloys become necessary to make sure industry gains maximum benefit from AM. This study specifically deals with the manufacturing of Al 7050 alloy, which is quite hardest alloy to manufacture using AM. The ultimate goal is to optimize the laser deposition parameters to deposit defect free Al 7050 alloy on rolled aluminum alloy substrate. Parameter optimization (laser power, powder flow rate, and scanning speed) gets difficult with the presence of various low melting and boiling point alloying elements such as Zn, Mg etc. Numerous other challenges faced while depositing Al 7050 alloy, are also briefly discussed in this article. Microstructural investigation using optical and scanning electron microscopy confirms greater than 99% component density. For best-achieved deposition, microstructural characterization and microhardness test were performed and results showed microhardness of 100 HV of as-deposited alloy. As Al 7050 alloy is responsive to precipitation hardening, solution heat treatment for different time periods followed by two stage aging was performed to enhance the mechanical properties of the as-deposited Al 7050 alloy and to simultaneously study the effect on microstructure evolution at the end of each heat treatment cycle. This study affirms that Al 7050 alloy can be successfully manufactured using direct laser metal deposition technique.