TY - JOUR
T1 - Strain-controlling mechanical behavior in noncrystalline materials. I
T2 - Onset of plastic deformation
AU - Kameda, J.
AU - Yokoyama, Y.
AU - Allen, T. R.
N1 - Funding Information:
This work was initiated while one of the authors (J.K.) was engaged in the U.S. Office of Naval Research Global (ONRG). He gratefully acknowledges the continuous support of Dr. F.M. Pestorius, former Technical Director of ONRG. T.R.A. gratefully acknowledges ONR's support of the Navy Reserve program.
PY - 2007/3/15
Y1 - 2007/3/15
N2 - In noncrystalline materials, a new critical condition is proposed that the controlling mechanism for the onset of plastic deformation depends directly on a critical strain. The yield strain-controlling the initiation of nonlinear plastic deformation, falls within a band of similar large values for all the classes of noncrystalline materials like oxide glasses, metallic glasses, and amorphous polymers, covering a large variation in Young's modulus. It has been shown in Zr-based noncrystalline alloys that heterogeneous and homogeneous plastic deformation initiate at a constant strain independent of the glass and supercooled liquid state. The magnitude of yield stress achieved at the constant critical strain drastically changes depending on the viscoelastic behavior and influences the deformation mechanisms. In glassy amorphous alloys with high elastic modulus, the formation of shear bands leads to their spontaneous growth under high yield strength, thereby no strain rate effect, while amorphous polymers with lower elastic modulus have thermally activated deformation. This strain criterion can also better explain the pressure effect on yield in amorphous polymers but the lack of pressure effect on metallic glasses, and the variation of the slip plane in tension and compression.
AB - In noncrystalline materials, a new critical condition is proposed that the controlling mechanism for the onset of plastic deformation depends directly on a critical strain. The yield strain-controlling the initiation of nonlinear plastic deformation, falls within a band of similar large values for all the classes of noncrystalline materials like oxide glasses, metallic glasses, and amorphous polymers, covering a large variation in Young's modulus. It has been shown in Zr-based noncrystalline alloys that heterogeneous and homogeneous plastic deformation initiate at a constant strain independent of the glass and supercooled liquid state. The magnitude of yield stress achieved at the constant critical strain drastically changes depending on the viscoelastic behavior and influences the deformation mechanisms. In glassy amorphous alloys with high elastic modulus, the formation of shear bands leads to their spontaneous growth under high yield strength, thereby no strain rate effect, while amorphous polymers with lower elastic modulus have thermally activated deformation. This strain criterion can also better explain the pressure effect on yield in amorphous polymers but the lack of pressure effect on metallic glasses, and the variation of the slip plane in tension and compression.
KW - Metallic and polymeric noncrystalline materials
KW - Shear bands
KW - Strain-controlling onset of plastic deformation
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U2 - 10.1016/j.msea.2006.10.030
DO - 10.1016/j.msea.2006.10.030
M3 - Article
AN - SCOPUS:33846799376
VL - 448
SP - 235
EP - 241
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
IS - 1-2
ER -