Reinforcement of magnesium with boron and tantalum filaments

Abstract

Composites of magnesium reinforced with continuous boron filaments (0.004 in. diam and 450 ksi tensile strength), and tantalum (0.010 in. diam and 78 ksi tensile strength) were fabricated by the infiltration technique. The tensile strength of the boron filament dropped to nearly half its original strength (230 ksi) as a result of exposure to molten magnesium. The tantalum filaments, however, maintained their original strength after infiltration. The stress-strain curves of B-Mg composites were of a typical brittle material. The elongation in each case approached that of the filament,i.e., about 0.35 pct. Ta-Mg composites failed essentially in ductile manner. The elongation of the composites with 0.4Vf was as high as 15.7 pct. The elastic modulus, tensile and yield strength, and fracture behavior of the two composite systems are discussed.