Evolution of L12 Ordered Precipitates in Cu–Fe–Si Alloy System and Its Influence on Potential Strength–Conductivity Properties

Sarkar, S and Sinha, SK and Palaniswamy, D and Srivastava, C and Chattopadhyay, K (2023) Evolution of L12 Ordered Precipitates in Cu–Fe–Si Alloy System and Its Influence on Potential Strength–Conductivity Properties. In: Metallography, Microstructure, and Analysis .

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Abstract

We report a copper-based alloy strengthened by L12 ordered precipitates and exhibiting a strength of 370 MPa and thermal conductivity of 290 (W/m.K) at 400 °C. The alloy is based on a Cu–Fe–Si system with the optimum composition of Cu-2.5atFe-2.5atSi and processed by the suction casting of the melt. The strengthening precipitates are crystallographically L12 ordered. The precipitates were evolved during post-solidification cooling and are coherent with continuous fcc copper matrix. Ordered precipitates show a cube-on-cube orientation relationship with the matrix. This feature promotes low interfacial energy and are useful for retaining high temperature strength. The composition of the precipitates was determined through 3D-APT studies and found to be ~ Fe68Cu9Si24 (at.). The coherent nature of the order–disorder interface and the low solid solubility of iron in the copper matrix impart resistance to coarsening at high temperatures. The high strength at room temperature (~ 690 MPa) is attributed to the coherency strain around the uniformly dispersed precipitates. However, order hardening plays a significant role at higher temperatures as coherency strain decreases with temperature, evidenced by the loss of strain contrast in TEM images. The combination of the significant stability of the microstructure and high-temperature strength makes this alloy attractive for high heat flux application at elevated temperatures domain. © 2023, ASM International.

Item Type:	Journal Article
Publication:	Metallography, Microstructure, and Analysis
Publisher:	Springer
Additional Information:	The copyright of this article belongs to Springer.
Keywords:	Coarsening; Heat flux; High strength alloys; Metallic matrix composites; Rapid solidification; Silicon alloys; Thermal conductivity; Alloy system; APT; Coherency strain; Copper matrix; Fe-Si alloys; High temperature strength; Highest temperature; L12 order; Suction casting; TEM; Copper alloys
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	10 Mar 2023 10:40
Last Modified:	10 Mar 2023 10:40
URI:	https://eprints.iisc.ac.in/id/eprint/80955

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