Effect of Ni and Mn Additions on the Ambient and High-Temperature Performance of Zr-Containing Al–Si–Cu–Mg-Based Alloys: Role of Precipitation Hardening

摘要: Alloys such as the 354.1 (Al–9 wt% Si–1.8 Cu–0.5 Mg) alloys show a greater response to heat treatment result of presence both Cu and Mg. These display excellent strength values at low high temperatures. Additions Zr, Ni Mn are expected maintain alloy performance still higher The present study was carried out investigate effects these additions on tensile properties castings ambient temperature (250 °C), using different holding times testing temperature. were prepared 0.2 Ti grain-refined alloy, comprising R (354.1 + 0.25 Zr) considered base or reference S Zr 2 Ni) U 0.75 Mn), containing Mn. latter two perform better under high-temperature conditions following 1-h stabilization 250 °C, displaying 226.64/230 MPa UTS 225/226 YS, respectively. For prolonged time (200 h however, reduced 111/96 90/78 YS. decrease in increase ductility observed after related softening, which occurs because overaging during equilibrium precipitates form, leading loss coherency strain between matrix.