New amorphous alloys in Al-Ca and Al-Ca-M (M = Mg or Zn) systems

Binary Al-Ca alloys were amorphized in the composition range of 9 to 11 at% Ca by melt spinning. The onset temperature of crystallization (T_x), Vickers hardness (H_v), Young's modulus and tensile fracture strength are in the range of 408 to 425 K, 130 to 153, 29 to 31 GPa and 390 to 480 MPa, respectively. The T_x and H_v values tend to increase with increasing Ca content. The crystallization takes place through two stages of Am → Am + Al → Al + Al₄Ca. The addition of Mg, Zn or TM (TM = Fe, Co, Ni, Cu) was also found to be effective for the extension of the glass formation range to the lower and higher Ca concentration sides. The formation of the amorphous phase in the Al-Ca binary alloys consisting of light weight metals is important to the development of Al-based alloys with high specific strength.