Formation of Bulk Metallic Glasses and Their Composites

Abstract

A great expansion in the number of alloy compositions known to give bulk metallic glasses (BMGs) has occurred in recent years. This progress is reviewed, and factors contributing to glass-forming ability are discussed. Practical strategies for pinpointing compositions with optimum glass-forming ability are presented, with examples of their use. Consideration is also given to the wide range of possibilities for BMG-based composites.

High glass-forming ability correlated with fragility of Mg–Cu(Ag)–Gd alloys

“…This is in contrast to most alloy systems, in which no such large D c has been found or at best, a couple of compositions can reach a D c of 20 mm. 2 The best BMG-forming composition is located at Mg 59.5 Cu 22.9 Ag 6.6 Gd 11 , with D c of 27 mm under copper mold casting. Several examples of Mg-Cu-Ag-Gd BMGs with D c ജ 25 mm are shown using x-ray diffraction patterns in Fig.…”

“…1,2 Among them, Mg-based BMGs are particularly interesting due not only to their high specific strength and low cost but also to their extraordinary glass-forming ability ͑GFA͒. [3][4][5][6] Recently, Mg-Cu-Ag-Gd BMGs with critical diameter ͑D c ͒ as large as 25 mm have been developed, 4 via the simple processing route of copper mold casting.…”

The Role of Casting Temperature in Preparation of Bulk Metallic Glasses

“…It is generally accepted that the introduction of second phase, such as fiber, dendrite, particle etc., into the amorphous matrix help to improve the properties of BMGs, especially plasticity, which is one of the principal restraints for BMGs' commercial applications [4][5][6][7][8]. In the present work, we also examined the effect of the precipitated crystalline CuZr phases on mechanical properties of samples using compression tests.…”

“…Like the steel industry, the database among processes, microstructures and properties for bulk metallic glasses (BMGs) should be built up in order to promote their commercial production and applications. In the past few decades the researchers in this field have concentrated on exploring alloy compositions to obtain large glass forming ability in all common alloy systems [4][5][6]. Significant progress has been achieved, as seen by the successful development of BMGs in many alloy systems including Al, Fe, Ni, Cu, Zr, Mg, Re (rare earth metals) -based alloys.…”

“…Significant progress has been achieved, as seen by the successful development of BMGs in many alloy systems including Al, Fe, Ni, Cu, Zr, Mg, Re (rare earth metals) -based alloys. The size of BMGs has been increased from micron to inch [4][5][6], and the plasticity of BMGs has improved by introducing particle [7] and fiber [8] to form BMG composites. However, very few studies focus on BMG processing conditions.…”