Formation of Cu–Zr–Al–Er bulk metallic glass composites with enhanced deformability

Deformation-Induced Martensitic Transformation in Cu-Zr-Zn Bulk Metallic Glass Composites

“…Recently, by using in situ high-accuracy X-ray diffraction analysis on Cu50Zr50 MG, Kalay et al found that only the B2 CuZr phase is observed at 1045 K while at 1002 K a mixture of B2 CuZr, Cu10Zr7, and CuZr2 crystals appear [43]. With decreasing temperature to 789 K, Cu10Zr7 and CuZr2 crystals can be found, which further confirms previous ex situ experimental results [30,31,34]. Therefore, during quenching of Cu-Zr-Zn melts, the B2 CuZr phase should be kept to room temperature.…”

“…For example, CuZr-based BMG composites with different sample sizes containing minor element additions such as Al, Ti, Ag, Ni, Co, Y, Er, V, W, or Ta have been successfully fabricated [20][21][22][23][24][25][29][30][31][32][33][34][35][36][37]. Two key requirements should be satisfied for the fabrication of CuZr-based BMG composites: (1) maintaining sufficiently high glass-forming ability (GFA) in order to fabricate large-sized BMG composites [20][21][22][23][24][25][29][30][31][32][33][34][35][36][37]; and (2) stabilization of metastable B2 CuZr phase in order to suppress its decomposition into equilibrium phases (EPs) [29][30][31][32][33][34]. Previous results [22,38] demonstrated that minor Co addition to CuZr alloys can dramatically enhance the thermal stability of the B2 CuZr phase but gravely deteriorate the GFA of CuZr-based alloys.…”

Correlation between the microstructures and the deformation mechanisms of CuZr-based bulk metallic glass composites

“…2(b)). The corresponding fracture strain/stress cannot be described by the ROM and the load-bearing models due to the following possible reasons: 9,12,17,[25][26][27][28][29][30][31] (i) the macroscopic softening from SBs and the work hardening caused by the MT are not taken into account and (ii) the interactions between SBs and the crystals, and the length-scale of the constituents compared to the characteristic plastic zone size are not sufficiently considered. Based on previous data and our observation for Cu 47.5 Zr 47.5 Al 5 BMGCs, 12,18 the optimum f cryst with respect to the fracture strength is determined to lie between 40 vol.% and 80 vol.% (inset in Fig.…”

Thermal stability and mechanical properties of Cu46Zr46Ag8 bulk metallic glass and its composites

“…However, the tendency of the B2 CuZr phase to precipitate in metastable CuZr-based alloys and its thermal stability are still not fully assessed. Furthermore, so far, only a limited number of in situ CuZr-based composites, which contain the ductile B2 phase, have been developed in systems such as Cu-Zr-Al [12,18], Cu-Zr-Al-Co [20], Cu-Zr-Al-Er [12,21] and Cu-Zr-Ti [22]. Therefore, it is necessary to extend the investigations regarding the phase formation and stability of CuZr-based BMGCs with good deformability in order to understand their deformation characteristics better and optimize this type of alloys.…”