Effect of oversolidus barothermal treatment on the microstructure and properties of binary hypereutectic Al-Cu alloys
Year: 2024
Type: article
Abstract: This study investigates the effect of oversolidus barothermal treatment (BTT) on microstructure and properties of binary alloys Al-22Cu and Al-27Cu (at.%), focusing on the pressure-induced shifts in solidus and liquidus temperatures. The pressure shift of the solidus and liquidus temperatures was established at a hydrostatic argon pressure of ~ 100 MPa using the differential barothermal analysis (DBA). The solidus temperature of both alloys increased by approximately 8 ℃ during heating, aligning closely with the equilibrium state diagram upon cooling. The liquidus temperature of the alloys at 100 MPa increased by 11 ℃ for Al-22Cu and by 14 ℃ for Al-27Cu compared to the phase diagram. Taking these results into account, barothermal treatment of the alloys was carried out at 100 MPa and 570 ℃ for 240 min (BTT1), as well as at 100 MPa and 562 ℃ for 10 min (BTT2). Processing of alloys at BTT1 leads to the primary Al 2 Cu particle size significant increase to lengths of 350–1500 μm and widths of 150–400 μm. During BTT1, the structure of the initial lamellar eutectic Al-Al 2 Cu is modified with the formation of discrete intermetallic particles, with the length and width being 15–240 and 1–3 µm, respectively. With a decrease in temperature and exposure time, a significantly less intense increase in the size of primary intermetallic compounds occurs, and a noticeable increase in discrete eutectic intermetallic compounds occurs. The microhardness reached 2043 MPa for the eutectic (initial Al-22Cu). For the intermetallic and the eutectic, the microhardness was 4189 and 2699 MPa, respectively (initial Al-27Cu); for intermetallic and the eutectic 4754 and 1382 MPa, respectively, for the Al-22Cu alloy processed at BTT1, and the eutectic microhardness for the Al-22Cu composition processed at BTT2 was 2409 MPa. The bending strength of alloys decreases after oversolidus BTT.
Source: Discover Materials
Institution: Baikov Institute of Metallurgy and Materials Science
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,490
OpenAlex ID: W4405575973