Solute trapping in Al-Cu alloys caused by a 29 Tesla super high static magnetic field

摘要

Solidification of Al-Cu alloys has been investigated using a 29 Tesla super high static magnetic field (SHSMF). The results show that, by imposing a 29 Tesla SHSMF, the size of primary phases and spacing of eutectic structure have been refined through the increase of undercooling which results from the suppression of diffusion coefficient. The diffusion coefficient of atoms in the liquid matrix decreases to be about 1.2 × 10⁻¹² m²/s. The lattice constants are reduced and high dislocation density forms in the primary phase, which induces a solute trapping effects. The spacing of (110) plane in Al2Cu is corrected to be 4.3123 Å and 4.2628 Å for Al-40 wt.%Cu alloys treated without and with a SHSMF. The spacing of (111) plane in Al is corrected to be 2.3351 Å and 2.3258 Å for Al-26 wt.%Cu alloys treated without and with a SHSMF. The compression yield strength has been improved by about 42% from 268 MPa to 462 MPa for Al-26 wt.%Cu and 42.5% from 248 MPa to 431 MPa for Al-40 wt.%Cu. The maximum elastic strain increases from about 2% to 4.3% for Al-26 wt.%Cu and from 2% to 4% for Al-40 wt.%Cu. It is expected that SHSMF is beneficial to process materials with high mechanical properties.