Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718
The effect of three important process parameters, namely laser power, scanning speed and laser stand-off distance on the deposit geometry, microstructure and segregation characteristics in direct energy deposited alloy 718 specimens has been studied. Laser power and laser stand-off distance were fou...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-01-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/10/1/96 |
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| author | Suhas Sreekanth Ehsan Ghassemali Kjell Hurtig Shrikant Joshi Joel Andersson |
| author_facet | Suhas Sreekanth Ehsan Ghassemali Kjell Hurtig Shrikant Joshi Joel Andersson |
| author_sort | Suhas Sreekanth |
| collection | DOAJ |
| description | The effect of three important process parameters, namely laser power, scanning speed and laser stand-off distance on the deposit geometry, microstructure and segregation characteristics in direct energy deposited alloy 718 specimens has been studied. Laser power and laser stand-off distance were found to notably affect the width and depth of the deposit, while the scanning speed influenced the deposit height. An increase in specific energy conditions (between 0.5 J/mm<sup>2</sup> and 1.0 J/mm<sup>2</sup>) increased the total area of deposit yielding varied grain morphologies and precipitation behaviors which were comprehensively analyzed. A deposit comprising three distinct zones, namely the top, middle and bottom regions, categorized based on the distinct microstructural features formed on account of variation in local solidification conditions. Nb-rich eutectics preferentially segregated in the top region of the deposit (5.4−9.6% area fraction, A<sub>f</sub>) which predominantly consisted of an equiaxed grain structure, as compared to the middle (1.5−5.7% A<sub>f</sub>) and the bottom regions (2.6−4.5% A<sub>f</sub>), where columnar dendritic morphology was observed. High scan speed was more effective in reducing the area fraction of Nb-rich phases in the top and middle regions of the deposit. The <100> crystallographic direction was observed to be the preferred growth direction of columnar grains while equiaxed grains had a random orientation. |
| first_indexed | 2024-12-20T18:26:27Z |
| format | Article |
| id | doaj.art-19dcc64a5f62413fa760870457bf27ff |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-12-20T18:26:27Z |
| publishDate | 2020-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-19dcc64a5f62413fa760870457bf27ff2022-12-21T19:30:09ZengMDPI AGMetals2075-47012020-01-011019610.3390/met10010096met10010096Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718Suhas Sreekanth0Ehsan Ghassemali1Kjell Hurtig2Shrikant Joshi3Joel Andersson4Department of Engineering Science, University West, 46186 Trollhättan, SwedenDepartment of Materials and Manufacturing, Jönköping University, 55111 Jönköping, SwedenDepartment of Engineering Science, University West, 46186 Trollhättan, SwedenDepartment of Engineering Science, University West, 46186 Trollhättan, SwedenDepartment of Engineering Science, University West, 46186 Trollhättan, SwedenThe effect of three important process parameters, namely laser power, scanning speed and laser stand-off distance on the deposit geometry, microstructure and segregation characteristics in direct energy deposited alloy 718 specimens has been studied. Laser power and laser stand-off distance were found to notably affect the width and depth of the deposit, while the scanning speed influenced the deposit height. An increase in specific energy conditions (between 0.5 J/mm<sup>2</sup> and 1.0 J/mm<sup>2</sup>) increased the total area of deposit yielding varied grain morphologies and precipitation behaviors which were comprehensively analyzed. A deposit comprising three distinct zones, namely the top, middle and bottom regions, categorized based on the distinct microstructural features formed on account of variation in local solidification conditions. Nb-rich eutectics preferentially segregated in the top region of the deposit (5.4−9.6% area fraction, A<sub>f</sub>) which predominantly consisted of an equiaxed grain structure, as compared to the middle (1.5−5.7% A<sub>f</sub>) and the bottom regions (2.6−4.5% A<sub>f</sub>), where columnar dendritic morphology was observed. High scan speed was more effective in reducing the area fraction of Nb-rich phases in the top and middle regions of the deposit. The <100> crystallographic direction was observed to be the preferred growth direction of columnar grains while equiaxed grains had a random orientation.https://www.mdpi.com/2075-4701/10/1/96laser metal deposition (lmd)columnar dendritic morphologyconstitutional supercoolingcolumnar to equiaxed transition (cet)high deposition rate |
| spellingShingle | Suhas Sreekanth Ehsan Ghassemali Kjell Hurtig Shrikant Joshi Joel Andersson Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 Metals laser metal deposition (lmd) columnar dendritic morphology constitutional supercooling columnar to equiaxed transition (cet) high deposition rate |
| title | Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 |
| title_full | Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 |
| title_fullStr | Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 |
| title_full_unstemmed | Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 |
| title_short | Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718 |
| title_sort | effect of direct energy deposition process parameters on single track deposits of alloy 718 |
| topic | laser metal deposition (lmd) columnar dendritic morphology constitutional supercooling columnar to equiaxed transition (cet) high deposition rate |
| url | https://www.mdpi.com/2075-4701/10/1/96 |
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