QCr0.8 Cu alloy /S06 stainless steel bimetal structure via In718 multi-interlayer fabricated by laser powder hybrid additive manufacturing
Baopeng Zhang, Wenqi Zhang, Haifeng Xiao, Haihong Zhu, Huanqing Yang, Yun Wang, Baijin Chen
Abstract
Fabricating high strength high conductivity (HSHC) Cu alloy inner parts by laser powder bed fusion (LPBF) and high-strength steel out layers on Cu alloy surfaces by laser-direct energy deposition (LDED), e.g., laser powder hybrid additive manufacturing (LPH-AM), has shown promise in the development of rocket engine thrust chambers with large thrust forces. In this study, we successfully fabricated a QCr0.8 HSHC Cu alloy/S06 stainless steel bimetal structure via In718 multi-interlayer using LPH-AM. We investigated the relative density, defects, microstructure, and interfacial characteristics of the bimetal structure in detail. The results indicate that the sample achieved up to 99.9% relative density with no naked defects and good metallurgical bonding at the QCr0.8/In718 and In718/S06 interfaces. The LPH-AM-ed QCr0.8/In718 interface exhibited a combination of columnar and equiaxed dendrites. The vertically combined sample exhibited an average ultimate tensile strength (UTS) and break elongation (EL) of 300.3 ± 10.6 MPa and 15.0 ± 1.4%, respectively, with fracture occurring at the QCr0.8 side. This study provides a new method for fabricating complex-shaped Cu/steel bimetal components, such as rocket engine thrust chambers.