Single-crystal Al-Cu50Zr50 metallic glass cold welds: tensile and creep behaviour

摘要

abstract_textpTensile and creep properties of dissimilar cold weld joints (Al (metal)-Cu50Zr50 (metallic glass)) are investigated using molecular dynamics simulations. Embedded atom method potential is used to model the interactions between Al-Cu-Zr atoms. Cold welding is carried out at three different velocities (20, 30 and 40 m/s) and for three interferences (0.4, 1.3 and 2.3 nm). The strength of the welded joints is measured using the tensile test carried out at a strain rate of 1.5 x 10(9)/s. Structure studies by radial distribution function analysis indicate amorphisation of Al in the weld regions. Tensile studies show that the maximum strength is obtained in the sample that is welded for 1.3 nm interference. Creep studies carried out over range of stresses (200-350 MPa) and temperatures (200-500 K) show very short primary creep and significant steady-state creep. The stress exponent n has two values; at lower stress, n = 1.2, and at higher stress, n = 4.06, respectively. The deformation mechanisms are observed to be slip by Shockley partial dislocation and by twinning in Al region. The icosahedral cluster population in metallic glass decreases as the temperature increases and contributes to large plastic strain./p/abstract_text