Cold spray additive manufacturing of Invar 36 alloy: microstructure,thermal expansion and mechanical properties

• 作者: Chaoyue Chen Yingchun Xie Longtao Liu Ruixin Zhao Xiaoli Jin Shanqing Li Renzhong Huang Jiang Wang Hanlin Liao Zhongming Ren
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2021,（13）
• 页码范围: 39-51
• 页数: 13页
• 语种: 英文

摘要

In this work,the Invar 36 alloys were manufactured using cold spray (CS) additive manufacturing technique.The systematic investigations were made on the microstructural evolution,thermal expansion and mechanical properties under as-sprayed (AS) and heat-treated (HT) conditions.XRD (X-ray diffraction)and ICP-AES (inductively coupled plasma atomic emission spectroscopy) analyses show that no phase transformation,oxidation,nor element content change have occurred.The X-ray computed tomography (XCT) exhibited a near fully dense structure with a porosity of 0.025％ in the helium-produced sample under as-sprayed condition,whereas the nitrogen-produced samples produced at 5 MPa and 800 ℃ show more irregular pore defects.He-AS sample shows a more prominent grain refinement than that of nitrogen samples due to the more extensive plastic deformation.The post heat-treatment exhibited a promoted grain growth,inter-particle diffusion,as well as the formation of annealing twins.Between 25 ℃ and 200 ℃,the nitrogen samples possessed lower CTE (coefficient of thermal expansion) values (1.53 × 10-6/℃) compared with those produced by casting and laser additive manufacturing.The He-AS samples exhibited a noticeable negative CTE value between 25 ℃ and 200 ℃,which may due to the significant compressive residual stress (-272 MPa) compensating its displacement with temperature increase during CTE test.The N2-HT and He-HT Invar 36 samples present a notable balance between strength and ductility.In conclusion,the CS technique can be considered as a potential method to produce the Invar 36 component with high thermal and mechanical performance.