On the observation of a new ternary MgSiCa phase in Mg-Si alloys

The Mg-Si binary system shows an exceptional potential material due prinicipally to the intermetallic phase Mg2Si present in those alloys. Chemical analysis of the alloys was performed by inductively coupled plasma from small chilled coupons. The ternary phase MgSiCa has been positively identified by means of two methods, first by scanning elctron microscopy (SEM) techniques and then by X-ray diffraction. The average atomic fraction is close to a stochiometric value of one-third for each element. Microhardness was evaluated using a Knoop indentor. The hardness values are only an approximation and further evaluation on larger particles with higher loads would have to be performed to ascertain the preliminary results.