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Mechanical performance of amorphous metallic cellular structures

Citation

Schramm, Joseph Paul (2010) Mechanical performance of amorphous metallic cellular structures. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:01292010-170058619

Abstract

Metallic glass and metallic glass matrix composites are excellent candidates for application in cellular structures because of their outstanding plastic yield strengths and their ability to deform plastically prior to fracture. The mechanical performance of metallic-glass and metallic-glass-matrix-composite honeycomb structures are discussed, and their strength and energy absorption capabilities examined in quasi-static compression tests for both in-plane and out-of-plane loading. These structures exhibit strengths and energy absorption that well exceed the performance of similar structures made from crystalline metals. The strength and energy absorption capabilities of amorphous metal foams produced by a powder metallurgy process are also examined, showing that foams produced by this method can be highly porous and are able to inherit the strength of the parent metallic glass and absorb large amounts of energy. The mechanical properties of a highly stochastic set of foams are examined at low and high strain rates. It is observed that upon a drastic increase in strain rate, the dominant mechanism of yielding for these foams undergoes a change from elastic buckling to plastic yielding. This mechanism change is thought to be the result of the rate of the mechanical test approaching or even eclipsing the speed of elastic waves in the material.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:amorphous metal; metal foam; honeycomb structures; mechanical properties;
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Johnson, William Lewis
Thesis Committee:
  • Johnson, William Lewis (chair)
  • Fultz, Brent T.
  • Conner, Robert Dale
  • Bhattacharya, Kaushik
Defense Date:9 October 2009
Record Number:CaltechTHESIS:01292010-170058619
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:01292010-170058619
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5543
Collection:CaltechTHESIS
Deposited By: Joseph Schramm
Deposited On:21 May 2010 22:34
Last Modified:12 Sep 2013 16:11

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