Study of residual stress and microstructural evolution in as-deposited and inter-pass rolled wire plus arc additively manufactured Inconel 718 alloy after ageing treatment

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:801

Article

Honnige, Jan¹  Seow, Cui Er^2,3  Ganguly, Supriyo¹  Xu, Xiangfang¹  Cabeza, Sandra⁴  Coules, Harry³  Williams, Stewart¹ 

[1] Cranfield Univ, Welding Engn Laser Proc Ctr, Cranfield MK43 0AL, Beds, England

[2] TWI Ltd, Natl Struct Integr Res Ctr, Granta Pk, Cambridge CB21 6AL, England

[3] Univ Bristol, Dept Mech Engn, Bristol BS8 1TR, Avon, England

[4] Inst Laue Langevin, 71 Ave Martyrs, F-38000 Grenoble, France

关键词: Additive manufacture;    Neutron diffraction;    Nickel;    Residual stress;    Microstructure;   

DOI  :  10.1016/j.msea.2020.140368

来源: Elsevier

【 摘 要 】

The manufacture of structural components made from nickel-based super alloys would benefit from the commercial advantages of Wire + Arc Additive Manufacturing (WAAM), as it is commonly expensive to process using other conventional techniques. The two major challenges of WAAM are process residual stress and undesired microstructure. Residual stress causes part distortion and build failures, while the as-deposited microstructure does not allow the common heat-treatment to be effective in achieving the desired mechanical properties. This paper focuses on understanding the microstructural features, phase formation and three-dimensional residual stress state variation in as-deposited and inter-pass rolled conditions and after solutionising, quenching and ageing. The thermal history from successive deposition and cold working were correlated to the phase formation and macro residual stress formation and subsequent evolution. The {311} family of crystallographic planes were used as atomic strain gauge to determine the macrostrain and analysis of three dimensional stress state in different processing conditions. The measured strain were corrected for the compositional variation by measuring EDM machined d(0) specimens manufactured under similar processing conditions. While the as deposited part show significant stress redistribution and distortion after removal from the main fixture, inter pass rolling was found to reduce part distortion significantly, the residual stress profile after inter-pass rolling showed highest tensile magnitude near the substrate while near the top of the deposit it was compressive as can be expected from the rolling process. The other two beneficial effects of inter-pass rolling on the microstructure are mitigation of the formation of undesired Laves-phase, thereby improving the response to solution treatment and aging together with significantly reduced grain size and texture. The application of inter-pass rolling reduces the potential part complexity, which however does not prevent the manufacture of common candidate parts, which are typically 1-to-1 replacements of forged, cast or machined from solid.

【 授权许可】

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