Microstructure, Corrosion and Mechanical Behavior of 15-5 PH Stainless Steel Processed by Direct Metal Laser Sintering

Author(s):  
Indu Avula ◽  
Adya Charan Arohi ◽  
Cheruvu Siva Kumar ◽  
Indrani Sen
Author(s):  
Rupinder Singh ◽  
Rishab ◽  
Jashanpreet S Sidhu

The martensitic 17-4 precipitation-hardenable stainless steel is one of the commercially established materials for structural engineering applications in aircrafts due to its superior mechanical and corrosion resistance properties. The mechanical processing of this alloy through a conventional manufacturing route is critical from the dimensional accuracy (Δ d) viewpoint for development of innovative structural components such as: slat tracks, wing flap tracks, etc. In past two decades, a number of studies have been reported on challenges being faced while conventional processing of 17-4 precipitation-hardenable stainless steel for maintaining uniform thickness of aircraft structural components. However, hitherto little has been reported on direct metal laser sintering of 17-4 precipitation-hardenable stainless steel for development of innovative functional prototypes with uniform surface hardness (HV), Δ d, and surface roughness ( Ra) in aircraft structural engineering. This paper reports the effect of direct metal laser sintering process parameters on HV, Δ d, and Ra for structural components. The results of study suggest that optimized settings of direct metal laser sintering from multifactor optimization viewpoint are laser power 100 W, scanning speed 1400 mm/s, and layer thickness 0.02 mm. The results have been supported with scanning electron microscopy analysis (for metallurgical changes such as porosity (%), HV, grain size, etc.) and international tolerance grades for ensuring assembly fitment.


Author(s):  
Sachin Alya ◽  
Chaitanya Vundru ◽  
Ramesh Singh ◽  
Khushahal Thool ◽  
Indradev Samajdar ◽  
...  

Abstract Additive manufacturing (AM) technology is gaining enormous popularity in the manufacturing industries. The continuous improvements made in the AM processes features development of 3D metallic prototypes as well as fully functional end-use components. Direct Metal Laser Sintering (DMLS) is a pre-placed powder bed based technique, in which a thin layer of powder is place over the build tray and the areas need to be sintered are exposed to the laser. In the current work the microstructural and mechanical behavior of Inconel 718 parts produced by DMLS are investigated. As the DMLS produces parts in a layer by layer fashion, the orientation of parts with respect to the build direction is an important criterion. Microstructure and mechanical properties of the produce differs depending upon the orientation. This paper emphasize on the variation of grain sizes and grain orientations developed in the components built with different orientations. Another common issue with the additive manufacturing is the development of the residual stresses in the components arising due to the differential thermal gradients experienced during processing. The variation of the residual stress generated in the produced parts has also been characterized and modeled.


Author(s):  
Genrik Mordas ◽  
Ada Steponavičiūtė ◽  
Aušra Selskienė ◽  
Jurijus Tretjakovas ◽  
Sergejus Borodinas

Additive manufacturing (AM) is a type of manufacturing technologies whereby the material is added a layer upon layer to produce a 3D object. Produced 3D parts are applied in such industry sectors as space, aviation, automotive, building and has excellent future promises. Ourdays, the commercialy promised technique for metal manufacturing is Direct Metal Laser Sintering (DMLS). Our study concentrated on the investigation of the mechanical properties of produced17-4H (stainless steel) parts using DMLS. The effect of the DMLS process parameters (laser power, scanning speed and energy density) on the ultimate strength, yield strength and Young’s modulus was determined. We showed an evolution of the microstructure. The detected defects were classified. This study allowed to determine the optimal regimes of DMLS for SS 17-4H and describe mechanical properties of the produced parts as well as helped to show future possibilities of DMLS development.


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