|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'504'585
Articles rated: 2609
24 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Heat treatment - microstructure - hardness relationships of new nickel-rich nickel-titanium-hafnium alloys developed for tribological applications | | Sean H. Mills
; Christopher Dellacorte
; Ronald D. Noebe
; Michael J. Mills
; Aaron P. Stebner
; Behnam Amin-Ahmadi
; | | Date: |
17 Sep 2020 | | Abstract: | The effects of various heat treatments on the microstructure and hardness of
new Ni56Ti41Hf3 and Ni56Ti36Hf8 (atomic %) alloys were studied to evaluate the
suitability of these materials for tribological applications. A solid-solution
strengthening effect due to Hf atoms was observed for the solution annealed
(SA) Ni56Ti36Hf8 alloy (716 HV), resulting in a comparable hardness to the
Ni56Ti41Hf3 alloy containing 54 vol.% of Ni4Ti3 precipitates (707 HV). In the
Ni56Ti41Hf3 alloy, the maximum hardness (752 HV), achieved after aging at 300C
for 12 h, was attributed to dense, semi-coherent precipitation of the Ni4Ti3
phase. Unlike the lenticular morphology usually observed within binary NiTi
alloys, a blocky Ni4Ti3 morphology formed within Ni56Ti36Hf3 due to a smaller
lattice mismatch in the direction normal to the habit plane at the
precipitate/matrix interface. The maximum hardness for Ni56Ti36Hf8 (769 HV) was
obtained after applying an intermediate aging step (300C for 12 h) followed by
normal aging (550C for 4 h). This two-step aging treatment induces dense
nanoscale precipitation of two interspersed precipitate phases, namely H-phase
and a new cubic Ni-rich precipitate phase, resulting in the highest hardness
exhibited yet by this family alloys. The composition of cubic Ni-rich
precipitates was measured using atom probe tomography to be approximately
Ni61.5Ti31Hf7.5, while HAADF-STEM revealed a 54 atom motif cubic structure (a=
8.87 Angstroms), and electron diffraction showed that the structure belongs to
the pm-3m (No. 221) space group. | | Source: | arXiv, 2009.07962 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER