1. Laser Beam Direct Energy Deposition of graded austenitic-to-martensitic steel junctions compared to dissimilar Electron Beam welding
- Author
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Flore Villaret, Yann Decarlan, Pascal Aubry, X. Boulnat, Satoshi Ohtsuka, Yasuhide Yano, Damien Fabrègue, Laboratoire d'Analyse Microstructurale des Matériaux (LA2M), Service des Recherches Métallurgiques Appliquées (SRMA), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département des Matériaux pour le Nucléaire (DMN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon, laboratoire d'ingénierie des surfaces et lasers (LISL), Service d'études analytiques et de réactivité des surfaces (SEARS), Département de Physico-Chimie (DPC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département de Physico-Chimie (DPC), Japan Atomic Energy Agency [Ibaraki] (JAEA), and Université de Lyon-Institut National des Sciences Appliquées (INSA)
- Subjects
Heat-affected zone ,Materials science ,Additive manufacturing ,Gradient material ,Mechanical properties ,02 engineering and technology ,Welding ,01 natural sciences ,law.invention ,law ,316L ,0103 physical sciences ,Electron beam welding ,Deposition (phase transition) ,General Materials Science ,Tempering ,Composite material ,010302 applied physics ,Austenite ,Mechanical Engineering ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Fe–9Cr–1Mo ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,Mechanics of Materials ,Martensite ,0210 nano-technology - Abstract
International audience; This article presents the Direct Metal Deposition (DMD) process as a method to build a graded austenitic-to-martensitic steel. Builds are obtained by varying the ratio of the two powders upon DMD processing. Samples with gradual transitions were successfully obtained thanks to the use of a high dilution rate from a layer to another. Long austenitic grains are observed on 316L side when martensitic grains are observed on Fe-9Cr-1Mo side. In the transition zone, the microstructure is mainly martensitic.Characterizations were performed after building and after a tempering heat treatment at 630°C during 8h and compared to dissimilar Electron Beam welds. Before heat treatment, DMD graded area has high hardness values (around 430 HV) due to fresh martensite formed during building. Tempering heat treatment allows reducing hardness in this area to 300 HV. EDS measurements indicate that the chemical gradient between 316L and Fe-9Cr-1Mo obtained by DMD is smoother than the chemical change obtained in Electron Beam (EB) welds. Microstructures in DMD are quite different from those obtained by EB welding. Hardness measurements in DMD samples and in welds exhibit similar behaviours: the weld metal and the Fe-9Cr-1Mo heat affected zone are relatively hard after welding because of fresh martensite, such as the DMD transition zone. These areas are all softened by the tempering heat treatment.
- Published
- 2021
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