Compositionally graded aluminum-silicon alloy fabricated via friction extrusion

Journal Article · 09 September 2022 · Materials Today Communications

DOI: https://doi.org/10.1016/j.mtcomm.2022.104423 · OSTI ID:1893894

Wang, Tianhao ^[1]; Li, Xiao  ^[1]; Gwalani, Bharat  ^[1]; Grant, Glenn J.  ^[1]; Powell, Cynthia A. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Herein, a novel solid-phase gradient alloying technique was developed for a high throughput composition-microstructure-mechanical property assessment. Friction extrusion of a two-piece billet setup facilitated the formation of a seamless compositionally graded aluminum (Al)-silicon (Si) extrudate rod, with Si concentration in Al matrix gradually increasing from ~1 at% at one end to ~7 at% at the other end of the rod. We observed a strong dependence of the Al grain size, morphology, and texture on the Si concentration. The Si particles pinned the recrystallized grain boundaries resulting in refined (< 10 µm) and textured grains in the high Si content region, while the Al grains in the low Si region are equiaxed, randomly textured, and with a larger average size (~50 µm). The hardness of Al-Si gradient extrudate increases by ~50% percent with a 6 at% increase in Si content due to Hall Petch and particle strengthening effects. Our approach demonstrates the use of a solid phase processing technique to successfully produce a defect-free continuously compositionally graded bulk components thus overcoming the limitations of porosity and material heterogeneities commonly observed in other techniques such as by additive laser deposition.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1893894
• Report Number(s): PNNL-SA-170396
• Journal Information: Materials Today Communications, Journal Name: Materials Today Communications Vol. 33; ISSN 2352-4928
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English