Title

Evaluation of Component Repair Using Direct Metal Deposition from Scanned Data

Abstract

In this work, the repair volume of AISI H13 tool steel samples with hemisphere-shaped defects was reconstructed through reverse engineering and the samples were repaired by laser-aided direct metal deposition (DMD) using Co-based alloys powder as the filler material. Microstructure characterization and elemental distribution of deposits were analyzed using optical microscope (OM), scanning electron microscope (SEM), and energy dispersive spectrometry (EDS). Mechanical properties of repaired samples were evaluated via tensile test and microhardness measurement. The experiment showed that a gap between deposits and substrate exists if only employing the tool path generated from the reconstructed repair volume but the gap can be removed by depositing an extra layer covering that region. Microstructure and tensile test confirmed strong metallurgical bond in the interface. Defect-free columnar structure dominated the deposits near the interface while other regions of deposits consisted of dendrite structure with interdendritic eutectics. The tensile test showed that the repaired samples have a higher ultimate tensile strength (UTS) and lower ductility compared with those of base metal. Fractography from tensile test showed repaired samples fractured brittlely at the deposits section with cracking propagating along the grain boundaries. The hardness measurement showed that the deposited layers have a much higher hardness in comparison to the substrate.

Department(s)

Mechanical and Aerospace Engineering

Research Center/Lab(s)

Intelligent Systems Center

Comments

This project was supported by National Science Foundation Grants CMMI-1547042 and CMMI 1625736, and the Intelligent Systems Center, Center for Aerospace Manufacturing Technologies, and Material Research Center at Missouri S&T. Their financial support is greatly appreciated.

Keywords and Phrases

3D printers; Alloy steel; Cobalt alloys; Deposition; Deposits; Fracture mechanics; Grain boundaries; Hardness; Metals; Microstructure; Repair; Reverse engineering; Scanning electron microscopy; Steel; Tensile strength; Tensile testing; Tool steel; Tools; Direct metal deposition; Elemental distribution; Energy dispersive spectrometry; Interdendritic eutectics; Laser-aided direct metal depositions; Microhardness measurement; Microstructure characterization; Ultimate tensile strength; Defects; Additive manufacturing

International Standard Serial Number (ISSN)

0268-3768; 1433-3015

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Springer Verlag, All rights reserved.

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