Fabrication of amorphous metal matrix composites by severe plastic deformation

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dc.contributor.advisor Hartwig , Karl Theodore en_US
dc.contributor.committeeMember Griffin , Richard B en_US
dc.creator Mathaudhu , Suveen Nigel en_US
dc.date.accessioned 2006 -10 -30T23 :32 :11Z
dc.date.accessioned 2014 -02 -19T19 :26 :46Z
dc.date.available 2006 -10 -30T23 :32 :11Z
dc.date.available 2014 -02 -19T19 :26 :46Z
dc.date.created 2006 -08 en_US
dc.date.issued 2006 -10 -30T23 :32 :11Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /4389
dc.description.abstract Bulk metallic glasses (BMGs ) have displayed impressive mechanical properties , but the use and dimensions of material have been limited due to critical cooling rate requirements and low ductility . The application of severe plastic deformation by equal channel angular extrusion (ECAE ) for consolidation of bulk amorphous metals (BAM ) and amorphous metal matrix composites (AMMC ) is investigated in this dissertation . The objectives of this research are a ) to better understand processing parameters which promote bonding between particles and b ) to determine by what mechanisms the plasticity is enhanced in bulk amorphous metal matrix composites consolidated by ECAE . To accomplish the objectives BAM and AMMCs were produced via ECAE consolidation of Vitreloy 106a (Zr58 .5Nb2 .8Cu15 .6Ni12 .8Al10 .3 -wt % ) , ARLloy #1 (Hf71 .3Cu16 .2Ni7 .6Ti2 .2Al2 .6 -wt % ) , and both of these amorphous alloys blended with crystalline phases of W , Cu and Ni . Novel instrumented extrusions and a host of postprocessing material characterizations were used to evaluate processing conditions and material properties . The results show that ECAE consolidation at temperatures within the supercooled liquid region gives near fully dense ( >99 % ) and well bonded millimeter scale BAM and AMMCs . The mechanical properties of the ECAE processed BMG are comparable to cast material : ? ? ? ?f = 1640 MPa , ? ? ? ?f = 2 .3 % , E = 80 GPa for consolidated Vitreloy 106a as compared to ? ? ? ?f = 1800 MPa , ? ? ? ?f = 2 .5 % , E = 85 GPa for cast Vitreloy 106 , and ? ? ? ?f = 1660 MPa , ? ? ? ?f = 2 .0 % , E = 97 GPa for ARLloy #1 as compared to ? ? ? ?f = 2150 MPa , ? ? ? ?f < 2 .5 % , E = 102 GPa for Hf52Cu17 .9Ni14 .6Ti5Al10 . The mechanical properties of AMMCs are substandard compared to those obtained from melt -infiltrated composites due to non -ideal particle bonding conditions such as surface oxides and crystalline phase morphology and chemistry . It is demonstrated that the addition of a dispersed crystalline phase to an amorphous matrix by ECAE powder consolidation increases the plasticity of the amorphous matrix by providing locations for generation and /or arrest of adiabatic shear bands . The ability of ECAE to consolidated BAM and AMMCs with improved plasticity opens the possibility of overcoming the size and plasticity limitations of the monolithic bulk metallic glasses . en_US
dc.format.extent 13312899 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject ECAE en_US
dc.title Fabrication of amorphous metal matrix composites by severe plastic deformation en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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Fabrication of amorphous metal matrix composites by severe plastic deformation. Available electronically from http : / /hdl .handle .net /1969 .1 /4389 .

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