Microstructural stability and high-temperature mechanical behavior of Al–Ni–Zr alloy strengthened by L1▫$_2$▫-Al▫$_3$▫Zr precipitates

Šmalc, Jan (author), Zaky, Adam (author), Markoli, Boštjan (author), Šturm, Roman (author)

Aluminum alloys based on the eutectic Al–Ni system are a promising class of lightweight materials for applications at elevated temperatures owing to the thermal stability of the eutectic Al▫$_3$▫Ni phase. In this study, the eutectic Al–Ni alloy was modified by the addition of 0.6 wt.% Zr to enhance the αAl matrix by precipitation strengthening. The alloys were cast and subjected to T5 heat treatment followed by long-term isothermal aging at 350 ◦C. A comprehensive study was carried out to evaluate the evolution of microstructure, micro-hardness and mechanical performance over time. The formation of fine, coherent L1▫$_2$▫-Al▫$_3$▫Zr precipitates contributed to significant strengthening, as reflected by a ~60% increase in microhardness and an approximately twofold improvement in room temperature (RT) yield strength. A TEM analysis of the L1▫$_2$▫-Al▫$_3$▫Zr precipitates showed relatively good thermal stability after 30 days. Despite the improved mechanical properties at room temperature, the alloy did not retain this improvement when tested at 300 ◦C. Nevertheless, these results provide a comprehensive insight into the aging and thermal stability of Al–Ni–Zr alloys.

• Language: English
• Keywords: aluminum–nickel eutectic, precipitation strengthening, microhardness, accelerated creep test
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering; NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 13 str.
• Numbering: Vol. 18, issue 13, art. 3068
• PID: 20.500.12556/RUL-170422
• UDC: 669
• ISSN on article: 1996-1944
• DOI: 10.3390/ma18133068
• COBISS.SI-ID: 241210371
• Publication date in RUL: 04.07.2025

Record is a part of a journal

• Title: Materials
• Shortened title: Materials
• Publisher: MDPI
• ISSN: 1996-1944
• COBISS.SI-ID: 33588485

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: eutektik aluminij-nikelj, izločevalno utrjevanje, mikrotrdota, pospešeni testi lezenja

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0270
• Name: Proizvodni sistemi, laserske tehnologije in spajanje materialov