In this paper

we have prepared Mg-Li based composites reinforced with boride by in situ synthesis. For mechanic properties of Mg-14Li-1Al-1Y based composites cannot meet the requirement of industrial applications

the research has prepared composites reinforced with boride based on Mg-9Li-1Al-1Y (its composition is (Mg-9Li-1Al- 1Y)-6B4C). The effect of Li content on microstructure and properties of the matrix alloys and composites were studied. The results show that compared with Mg-14Li-1Al-1Y

the dual phase microstructure of Mg-9Li-1Al-1Y is finer and the mechanical properties are improved. Compared with Mg-9Li-1Al-1Y

the hardness and the tensile strength of (Mg-9Li- 1Al-1Y)-6B4C are enhanced by 66% and 31.33%

respectively

while the elongation decreases by 15.5%. Compared with (Mg-14Li-1Al-1Y)-6B4C

the yield strength of (Mg-9Li-1Al-1Y)-6B4C decreass by 15.4%

the hardness increases by 29.3%

and the tensile strength and elongation remains unchanged. The above experimental results show that the mechanical properties of composites have not been improved with the deduce of Li content. It does not reach the expectation that composite strength can be improved with strength increase of corresponding alloys. The matrix strengthening is too weak to reflect in comparison to the second phase strengthening and fine-grain strengthening of Mg-Li based composite reinforcement mechanism.