Correlation of Microstructure with Mechanical Properties of Zr-Based Amorphous Matrix Composite Reinforced with Tungsten Continuous Fibers and Ductile Dendrites

Abstract

A Zr-based amorphous matrix composite reinforced with tungsten continuous fibers in an amorphous LM2 alloy matrix containing ductile beta dendrites was fabricated without pores or defects by the liquid pressing process, and its tensile and compressive properties were examined in relation with microstructures and deformation mechanisms. Overall, 68 vol pct of tungsten fibers were distributed in the matrix, in which 35 vol pct of beta dendrites were present. The LM2 composite had the greatly improved tensile strength and elastic modulus over the LM2 alloy, and it showed a stable crack propagation behavior as cracks stopped propagating at the longitudinal cracks of tungsten fibers or ductile beta dendrites. According to the compressive test results, fracture did not take place at one time after the yield point, but it proceeded as the applied loads were sustained by fibers, thereby leading to the maximum strength of 2432 MPa and plastic strain of 16.4 pct. The LM2 composite had the higher strength, elastic modulus, and ductility under both tensile and compressive loading conditions than the tungsten-fiber-reinforced composite whose matrix did not contain beta dendrites. These distinctively excellent properties indicated a synergy effect arising from the mixing of amorphous matrix and tungsten fibers, as well as from the excellent bonding of interfaces between them.