MATERIALS TRANSACTIONS
Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Thermal Stability and Mechanical Properties of Spray-Formed and Melt-Spun Al89La6Ni5 Metallic Glass Matrix Composites
M.-L. Ted GuoChi Y. A. TsaoK. F. ChangJ. C. HuangJ. S. C. Jang
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2007 Volume 48 Issue 7 Pages 1717-1721

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Abstract

A spray-formed Al89La6Ni5 metallic glass matrix composite plate was obtained in thickness of 1 mm and diameter of 200 mm, comprising over 64% primary crystals (e.g. Al11La3) uniformly dispersed in the glass matrix. The microstructure can not be achieved by annealing corresponding amorphous precursor. The crystals existing in the glass matrix were found to increase the hardness of the composite. Through nanoindentation test, the hardness and modulus of the composite at ambient temperature were found superior than its amorphous ribbon counterpart. The hardness of the composite was estimated with the rule of mixture from the constituents to be 4.4 GPa, which agreed well with the nanoindentation results. From loss modulus measurement and TMA test at elevated temperatures, a weak Tg signal in the range of 213–240°C was revealed in the as-spray-formed composite. Furthermore, the dimension shrinkage of the composite was only 0.5% during the TMA test, which is much smaller than that of amorphous ribbon counterpart by up to 20%. The enhanced hardness by constituent second phases and the dimension stability of the composite are associated with their inherent microstructure, the primary crystals in particular.

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© 2007 The Japan Institute of Metals and Materials
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