Enhancement of high temperature strength of Al-Cu alloys by minor alloying and hot working process

Mondol, S and Bansal, U and Dhanalakshmi, P and Makineni, SK and Mandal, A and Chattopadhyay, K (2022) Enhancement of high temperature strength of Al-Cu alloys by minor alloying and hot working process. In: Journal of Alloys and Compounds, 921 .

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Abstract

The paper reports the design and development of wrought Al-Cu alloys that retain high strength until 250 °C. It is achieved by minor alloying of Zr (<0.15 at%) and Nb (<0.1 at%) and inducing precipitation of stable nanometric dispersion of L12 ordered precipitates during controlled thermomechanical treatment (rolling) of cast alloys before conventional heat treatment (solutionizing and ageing). The rolling temperature was optimized to 450 °C by quantitatively evaluating the size distribution of the dispersions at different rolling temperatures. The dispersions influence the microstructure and the nature of the precipitation of the strengthening θ′ plates during subsequent conventional heat treatment. The microstructure of the processed alloy show stability at high temperatures. The atom probe tomography reveals Zr enrichment at the broad faces of θ′ plates. The presence of Zr plays a critical role in the high-temperature strength by promoting the stability of θ′ precipitates and resisting its coarsening. The composite microstructure of Al-Cu-Nb-Zr alloy displayed yield strength (YS) of 415 MPa and 220 MPa at room temperature and at 250 °C, which are higher by 26 % and 45 % respectively as compared to a commercial Al-Cu based alloy (2219-T851). The present results are promising for developing wrought Al alloys for high-temperature applications.

Item Type:	Journal Article
Publication:	Journal of Alloys and Compounds
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to the Elsevier Ltd.
Keywords:	Al-Cu based alloys; Atom probe tomography; Electron microscopy; High-temperature strength; L12 precipitates; Thermo-mechanical treatment
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 Jul 2022 10:38
Last Modified:	27 Jul 2022 10:38
URI:	https://eprints.iisc.ac.in/id/eprint/74984

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