Fabrication of multi-lamina metallic-glass/aluminium composites by explosive compaction

Abstract

Metallic glasses offer several attractive physical properties; however, their mechanical properties have proven difficult to exploit. They exhibit high biaxial strength, i.e. unlike high-strength fibres they exhibit strength in both the axial and transverse directions, but can only be obtained in the form of thin ribbons. The ribbon form of the glass along with its biaxial strength makes it most attractive as a reinforcement phase for composite materials and some work has been undertaken with this as its aim. Kadir et al. [1] has shown that metallic glass can be incorporated into an epoxide matrix to produce reinforcement and Cytron [2] has incorporated metallic glass into an aluminium alloy matrix. However, the metastable nature of metallic glasses always leads to difficulties during composite fabrication. This has been partially overcome by the use of low thermal excursion techniques such as incorporation into polymeric matrices, or by the use of temperature-resistant glasses which are less susceptible to crystallization during the fabrication cycle. However, in addition to these techniques, dynamic processing can be employed, where the timespan of the thermal excursion is small, thus limiting crystallization effects. This type of technique is particularly suited to the fabrication of metal matrix composites (MMC) containing the iron-based metalmetalloid glasses whose crystallization temperatures are typically in the range 400 to 600 ° C. Dynamic compaction has been employed to consolidate metallic glass ribbon into "monolithic" material by several workers [3, 4] without any observed crystallization, although anneal-embrittlement of the glass may occur [5]. This has been carried out by explosive consolidation [3]. However, little work has been conducted on the use of these techniques for the consolidation of metallic glass into MMC. Cline and Hopper [6] have demonstrated that metallic glasses can be explosively clad onto steel substrates and Ahmed [7] has shown that they can be incorporated into model MMC structures. None of