Experimental input for the design of metallic glass/crystalline composites
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The Ohio State University / OhioLINK
2013
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13855124842021-08-03T06:20:51Z Experimental input for the design of metallic glass/crystalline composites Hutchinson, Nicholas W. Materials Science metallic glass composite microstructure digital image correlation Bulk metallic glasses often exhibit exceptional strength and large elastic strains, but the structural applications of bulk metallic glasses are limited by their extremely low tensile ductility. Below the glass transition temperature of the alloy, plastic deformation occurs primarily in narrow shear bands, which propagate unimpeded through the monolithic glass structure, resulting in catastrophic failure under tensile loading. A number of studies have added crystalline reinforcements to the glassy matrix in an effort to block shear band propagation and increase ductility. The reinforcements in these bulk metallic glass matrix composites (BMGMC’s) can be added as ex situ particles or fibers infiltrated by the glass- forming liquid, or can be formed in situ, either via devitrification of the glass during post-processing or as a second phase that precipitates from the melt during solidification . The size, distribution, and mechanical properties of the reinforcement phase have significant impact on the ductility of the composite. However, surprisingly little quantitative microstructural information is available for BMGMC’s, particularly those formed by precipitation from the melt.In this work, we examine two in situ BMGMC’s in which a ductile crystalline phase precipitates during solidification of the melt, resulting in a complex dendritic structure embedded in a continuous glass matrix. A 3D serial sectioning process was used to image the microstructure at regular intervals by removing slices of material using a dual beam focused ion – scanning electron microscope (FIB). Due to the complex nature of the microstructure, measurements of key features were conducted using a 3D measurement method that was developed for this purpose. Experiments were also conducted to provide experimental input for the development and tuning of finite element models. Changes in the elastic modulus of the composite were evaluated over a range of stresses that encompassed the yield point of the composite. An interesting increase in the modulus was observed prior to yielding. The work is concluded with a study of the accumulation of strain within the composite microstructure during tensile loading. The strain was determined and evaluated by a digital image correlation method. 2013 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1385512484 http://rave.ohiolink.edu/etdc/view?acc_num=osu1385512484 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Materials Science metallic glass composite microstructure digital image correlation |
| spellingShingle |
Materials Science metallic glass composite microstructure digital image correlation Hutchinson, Nicholas W. Experimental input for the design of metallic glass/crystalline composites |
| author |
Hutchinson, Nicholas W. |
| author_facet |
Hutchinson, Nicholas W. |
| author_sort |
Hutchinson, Nicholas W. |
| title |
Experimental input for the design of metallic glass/crystalline composites |
| title_short |
Experimental input for the design of metallic glass/crystalline composites |
| title_full |
Experimental input for the design of metallic glass/crystalline composites |
| title_fullStr |
Experimental input for the design of metallic glass/crystalline composites |
| title_full_unstemmed |
Experimental input for the design of metallic glass/crystalline composites |
| title_sort |
experimental input for the design of metallic glass/crystalline composites |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2013 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1385512484 |
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AT hutchinsonnicholasw experimentalinputforthedesignofmetallicglasscrystallinecomposites |
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1719435046726664192 |