Consolidation of Ni 60 Nb 40 Metallic Glass Strips into Metal Matrix Composites
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CONSOLIDATION OF Ni 60Nb40 METALLIC GLASS STRIPS INTO METAL MATRIX COMPOSITES S. J. CYTRON, 07801, ATTN:
US ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND, DRDAR-SCM-P (Bldg. 355).
DOVER,
NJ
ABSTRACT To fully utilize the promising mechanical properties of metallic glasses, consolidation techniques need to be developed to incorporate them into large bulk forms. This paper describes preliminary results on the consoli-
dation of Ni
Nb
metallic glass strips into an aluminum
. 60 40 alloy matrix. Tne consolidation was achieved without the degradation of the metallic glass by employing a superThe plastic aluminum alloy as the matrix material. consolidations were accomplished at a superplastic forming temperature compatible with the metal matrix material and sufficiently below the critical 650°C crystallization Initial temperature of the Ni Nb40 metallic glass. studies employed an atuminum - 5% calcium - 5% zinc alloy as the metal matrix material.
INTRODUCTION Numerous investigations into consolidation methods for metallic glasses One approach not previously considered, that is under have been reported (1). study at this laboratory, is the consolidation of metallic glass ribbons into metal matrix composites. Previous studies of composites reinforced with meIn tallic glass ribbons have dealt with only organic matrix systems (2-4). these studies the consolidation temperature did not exceed 4500 K (4) for fear Conof degrading either the organic material or the metallic glass ribbon. solidation studies where a metallic glass/metal bond had been formed are rare. S. Takayoma and R. G. Fehrman reported cladding copper and aluminum wire with Leibermann (6,7), a Fe-Mo-B metallic glass sheathing by repeated swaging (5). in studying the consolidation of metallic glass ribbons by extrusion, produced In both of these a metallic glass/metal bond at the steel extrusion jacket. studies, the strength of the interfacial bond was not assessed with a view towards developing a scheme whereby metallic glass ribbons could be effectively In the incorporated as reinforcement members within metal matrix composites. present work, advantage is taken of the superplastic forming property of an aluminum alloy to obtain the required strong interfacial bonding between the materials. A Ni 6Nb metallic glass ribbon was chosen as the reinforcement ribbon in the composie system under study because of its ductility (8,9) For the metal matrix, a superand 925°K crystallization temperature (10). plastic aluminum alloy, Al-5 wt.% Ca-5 wt.% Zn (11) was chosen because its 775 K thermoforming temperature was well below the critical crystallization temperature of the incorporated metallic glass ribbon. EXPERIMENTAL METHOD The metal matrix composite was fabricated by hot pressing an evacuated copper (OFHC grade) capsule (0.95 cm dia X 3cm) containing a stack of alterThe superplastic nating strips of the aluminum alloy and the metallic glass.
146 alloy was acquired in sheet form in the cold rolled condition and cut into strips 0.1 x 0.4 x 2.5 cm. The st
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