Microstructure and strengthening mechanisms of 90W–7Ni–3Fe alloys prepared using laser melting deposition

Y.P. Wang, S.Y. Ma, X.S. Yang, Y.Z. Zhou, X. Liu, J.F. Li, J.J. Zhang, C. Li, X.Y. Wang, G. M. Le*, Y. Zhang*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The microstructure and mechanical properties of a 90W–7Ni–3Fe heavy alloy manufactured using laser melting deposition (LMD) have been investigated with a goal of understanding the LMD process and the relevant strengthening mechanisms. A reference sample prepared using liquid phase sintering (LPS) with similar composition has been used for comparison to isolate effects of the processing rate. The results show that the nearly fully-dense LMD sample consists of two periodically alternating sublayers containing different volume fractions of W particles. Compared to the reference LPS sample, the LMD sample has a higher W content in the binder matrix, a more refined microstructure, a higher dislocation density and a lower contiguity between W particles. Furthermore, the LMD sample has a yield strength of 822 ± 30 MPa, which is about 200 MPa higher than that of the reference LPS sample. This strength difference is quantitatively analyzed based on the microstructural observations. It is shown that the increased fraction of W-matrix interfaces, a higher interface bonding strength and more pronounced constraint effects, resulting from the higher processing temperature and fast cooling of LMD, provide extra strengthening. The present study provides an important basis for optimizing the LMD process for manufacture of high W content tungsten heavy alloys with improved mechanical properties.
Original languageEnglish
Article number155545
JournalJournal of Alloys and Compounds
Volume838
Number of pages19
ISSN0925-8388
DOIs
Publication statusPublished - 2020

Bibliographical note

GA no. 788567

Keywords

  • Refractory metals
  • Laser deposition
  • Composites
  • Microstructure
  • Mechanical property

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