ABSTRACT

The precise shape of a shift block support for the turbine blade of a hovercraft was additively manufactured using 17–4 precipitation-hardened stainless steel (STS 630) powder through laser powder bed fusion (LPBF). Subsequently, heat treatment under the H900 condition increased the yield strength and fracture strain of the shift block to 1313 MPa and 11.5%, respectively, and enhanced its corrosion resistance to seawater. This improvement in mechanical and physical properties is primarily because Cu precipitates were uniformly distributed at the interfacial boundaries along with the simultaneous suppression of the formation of Cr₂₃C₆ precipitates with weak corrosion resistance. Furthermore, this was attributed to the phase transformation from the as-built STS 630 comprising a mixture of austenite, ferrite, and martensite to a dual mixture of ferrite and martensite after the heat treatment. Thereafter, we topologically optimised the shift block and adopted a lattice structure to apply the design for additive manufacturing (DfAM).

摘要

用于气垫船涡轮叶片的换挡块支撑的精确形状，是通过17-4沉淀硬化不锈钢（STS 630）粉末通过激光粉末床熔合（LPBF）叠加制造的。随后，在H900条件下进行热处理，将换档块的屈服强度和断裂应变分别提高到1313 MPa和11.5％，并增强了其对海水的耐腐蚀性。机械和物理性能的改善主要是因为Cu析出物在界面边界处均匀分布，同时抑制了Cr ₂₃ C ₆的形成。耐腐蚀性较弱的析出物。此外，这归因于从热处理后的包括奥氏体，铁素体和马氏体的混合物的建成的STS 630到铁素体和马氏体的双重混合物的相变。此后，我们对换挡块进行了拓扑优化，并采用了晶格结构以将设计应用于增材制造（DfAM）。