Effect of the microstructural characteristics of die-cast ADC12 alloy controlled by Na and Cu on the mechanical properties of the alloy

The mechanical properties of a die-cast Al–Si–Cu alloy (DC ADC12) were improved using new processing techniques that induce grain refinement and precipitation hardening. Several gravity-cast ADC12 (GC samples with different microstructural sizes also evaluated to better understand the material DC ADC12. indicate has both advantages (fine grains) disadvantages (defects). can be by adding Na before T5 process. was achieved introducing benign inexpensive NaHCO3 rather than metallic Na. elements including sodium oxide retained in melt cause fine spherical eutectic structures form α-Al matrix interrupting Si phase growth. phenomenon detected via three-dimensional atom probe tomography analysis. Precipitation hardening Al subjecting it treatment large amount Cu, replacing T6 treatment, for 3 h at 175 °C, because die casting process replaced solid solution owing its high cooling rate. occurred grain-refined ADC12-Na sample during process, which verified situ observation microstructure laser microscopy heating processes. Al2MgCu, CuAl2, particles, from precipitates obtained produced phase. demonstrated resulted remarkable improvements ultimate tensile strength fracture strain