A continuous production process was developed for coating bulk metallic glasses on the metallic wire surface. The effects of processing parameters, including the drawing velocity and coating temperature, on the coating thickness were investigated. It is found that the coating thickness increases with the increase in drawing velocity but decreases with the increase in coating temperature. A fluid mechanical model was developed to quantify the coating thickness under various processing conditions. By using this theoretical model, the coating thickness was calculated, and the calculated values are in good agreement with the experimental data.
Bulk metallic glass (BMG) composites with the austenite B2 phase as reinforcement macroscopically showed strain hardening behavior due to the plasticity induced by martensitic transformation during deformation. Relationship between characteristics of the B2-CuZr reinforcing phase and uniaxial compressive properties of CuZr-based BMG composites was studied. Mechanical properties of these BMG composites were found to depend on not only the reinforced phases but also the amorphous matrix,and the yield and fracture strength can be roughly estimated by the rule of mixture principle. Distribution of the reinforced B2-CuZr phase has an important impact on the compressive plasticity even for the composites with a similar volume fraction of the crystalline phase.
To address the main stumbling-block of bulk metallic glasses （BMGs）, i.e., room temperature brittleness, designing BMG matrix composites has been attracted extensive attention. Up to date, BMG composites in various alloy systems have been successfully developed by forming crystalline phases embedded in the amorphous matrix through either ex-situ or in-situ methods. In this paper, a brief review of our recent work in this topic will be presented and the novel approaches to improving composite formability and mechanical properties will also be highlighted. The main purpose of this manuscript is not to offer a comprehensive review of all the BMG composites, but instead focuses will be placed on illustrating recently developed advanced BMG composites including Fe-based BMG composite with no metalloids, AI-based BMG composite and BMG composites reinforced by the TRIP （transformation-induced plasticity） effects. The basic ideas and related mechanisms underlying the development of these novel BMG composites will be discussed.
The effects of Sn and Ga additions on the glass forming ability （GFA） of （A186LasNi9）100_xSnx（x=0, 0.2, 0.3, 0.5, 0.7, 1 and 2 at.%） and （Al86LasNi9）100_xGax（x=0, 0.2, 0.5, 1 and 1.5 at.%） alloys were systematically investigated. Unlike common microal- loying methods, both Sn and Ga have a positive heat of mixing with the main component of A1. Our analysis confirmed that proper Sn addition can suppress the strong formation of a-A1 and enhance the GFA due to the positive heat of mixing between Sn and AI and the large difference in their atomic sizes. While the addition of Ga to the base alloy acted as the nucleation cites for ct-Al and accelerated precipitation of the ct-A1 phase, thus deteriorating the GFA.
