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Improving the Fracture Toughness and Ductility of Liquid-Phase Sintered WNiFe Tungsten Heavy Alloys by High-Temperature Annealing

Journal Article · · Materials
DOI:https://doi.org/10.3390/ma16030916· OSTI ID:2417875
 [1];  [2]
  1. Univ. of California, Santa Barbara, CA (United States); Univ. of California, San Diego, CA (United States)
  2. Univ. of California, Santa Barbara, CA (United States)
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Tungsten heavy alloys (WHAs) are candidates for use in fusion reactor divertors. Here, we characterize liquid-phase sintered WHAs with 90, 92.5, 95, and 97 (wt.%) tungsten (W), with a balance of a 0.7Ni–0.3Fe ductile phase. These WHAs show remarkable room temperature (RT) fracture toughness at the maximum load, KJm, ranging from ≈ 38 to 107 MPa√m, compared to a monolithic W toughness of ≈ 8 MPa√m. In most cases, the fracture of WHAs occurs through stable crack tearing. However, the 97W WHA has the lowest toughness and fracture elastically in all but the smallest specimens. As lower Ni contents are desirable for fusion application, we explore the potential for improving the ductility and KJm of WHAs using vacuum annealing at 1300 °C for 24 h. The microstructural observations reveal negligible changes in the WHA microstructure and constituent compositions. While annealing reduces the Vickers microhardness (HV), it does not significantly change the RT yield (σy) and ultimate (σu) strengths but results in beneficial increases in total elongation in the 95 and 97W WHAs by a factor of 2. RT tests on the precracked three-point-bend (3PB) bars show that annealing increases the KJm of these WHAs, and in the case of the 97W WHA, the increase is from 42 to 92%, depending on the size of the specimen. Toughening is due to enhanced crack tip process zone microcracking and dilatation.

Research Organization:
Univ. of California, Santa Barbara, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); National Science Foundation (NSF)
Grant/Contract Number:
FG03-94ER54275
OSTI ID:
2417875
Journal Information:
Materials, Journal Name: Materials Journal Issue: 3 Vol. 16; ISSN 1996-1944
Publisher:
MDPICopyright Statement
Country of Publication:
United States
Language:
English

References (24)

Effect of vacuum-treatment on mechanical properties of W-Ni-Fe heavy alloy journal May 1983
Processing strategy for consolidating tungsten heavy alloys for ordnance applications journal January 2001
On the remarkable fracture toughness of 90 to 97W-NiFe alloys revealing powerful new ductile phase toughening mechanisms journal March 2020
Thermal stability of a highly-deformed warm-rolled tungsten plate in the temperature range 1100–1250 °C journal October 2015
Investigations on tungsten heavy alloys for use as plasma facing material journal November 2017
Behaviour of tungsten alloy with iron and nickel under repeated high temperature plasma pulses journal February 2020
Mechanical characterization and modeling of the heavy tungsten alloy IT180 journal May 2015
Comparison of tungsten nano-tendrils grown in Alcator C-Mod and linear plasma devices journal July 2013
Results on the use of tungsten heavy alloys in the divertor of ASDEX Upgrade journal December 2018
Impact of heat treatment on tensile properties of 97W 2Ni 1Fe heavy alloy journal December 2018
Plasma and X-ray radiation-induced damage mechanisms in a tungsten heavy alloy journal October 2020
Impact of microstructural properties on hardness of tungsten heavy alloy evaluated by stand-off LIBS after PSI plasma irradiation journal November 2020
On the influence of specimen size and geometry on the fracture toughness of tungsten heavy metal alloys journal December 2022
Fabrication, characterization, and mechanical properties of 93W–4.9Ni–2.1Fe/95W–2.8Ni–1.2Fe–1Al2O3 heavy alloy composites journal June 2015
Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys journal July 2015
Tensile mechanical properties and fracture behavior of tungsten heavy alloys at 25–1100 °C journal October 2015
Tensile deformation and fracture properties of a 14YWT nanostructured ferritic alloy journal October 2016
The effect of hot rolling on the strength and fracture toughness of 90W–7Ni3Fe tungsten heavy metal alloys journal September 2021
Recrystallization behavior of hot-rolled pure tungsten and its alloy plates during high-temperature annealing journal May 2018
Prediction of temperature range for the onset of fuzz formation in helium-plasma-implanted tungsten journal August 2020
Recent Progress in Processing of Tungsten Heavy Alloys journal December 2014
Fracture Mechanics book June 2005
Effect of heat Treatment on the Mechanical Properties and Fracture Behavior of Tungsten Heavy Alloys journal January 2017
Engineering approach for elastic-plastic fracture analysis report July 1981

Figures / Tables (14)

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Related Subjects

36 MATERIALS SCIENCE
Chemistry
Materials Science
Metallurgy & Metallurgical Engineering
Physics
annealing
ductile phase toughening
fracture toughness
high-temperature heat treatment
microstructure
tungsten heavy alloy