Feasibility Study on Additive Manufacturing of Liquid Rocket Combustion Chamber

Abstract

Additive manufacturing is recently attracting attention as an innovative production technology of aerospace components to drastically reduce manufacturing time and cost, and improve design flexibility and productivity. In this paper, the feasibility of applying the direct metal laser sintering (DMLS) method to a regeneratively cooled combustion chamber inner liner made of copper alloy and that of applying the laser metal deposition (LMD) method to a combustion chamber outer shell made of Ni-based alloy were investigated. The DMLS and the LMD parameters, such as laser power, beam scan speed, and so on were investigated to establish the fabrication conditions. Heat treatment conditions such as, hot isostatic pressing (HIP), solution treatment, and aging were also investigated to improve the thermal conductivity and the tensile strength of the copper alloy. Interfacial bonding strengths between the copper alloy substrate and the Ni-based alloy outer layer were also evaluated. The 30 kN class LOX/LCH₄ combustion chamber inner liner in which coolant passages were located circumferentially in the liner wall was successfully fabricated by DMLS, and the molding of the outer shell around the inner liner by LMD is now being prepared.