G.M. Stoica
University of Tennessee
Ultimate tensile strengthFatigue limitDeformation (engineering)Communication channelComposite materialCompression (physics)MetallurgyMaterials sciencePerpendicularDeformation (meteorology)Deformation mechanismMagnesium alloyEqual channel angular extrusionExtrusionAlloyTexture (crystalline)Slip (materials science)MagnesiumDuctilityCrystal twinningNeutron diffractionPlasticityAnisotropyMicrostructurePressing
12Publications
9H-index
1,247Citations
Publications 12
Newest
#1Sean R. Agnew (ORNL: Oak Ridge National Laboratory)H-Index: 54
#2T.M. LilloH-Index: 5
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 8 authors...
Equal channel angular extrusion IECAE) offers the potential to introduce \cry large strains into a metal workpiece uithout changing its cross-section. Hence. i t could be an attractlie technique for developing a tine-grained forging stock uith good forming characteristics. Magnesium alloys are ideal candidates to benetit from the ECAE technique, because of their poor forming characteristics due to a hexagonal close packed crystal structure and a low nielting point, which allows them to be ECAE p...
7 CitationsSource
#1Sean R. Agnew (UVA: University of Virginia)H-Index: 54
#2G.M. Stoica (UT: University of Tennessee)H-Index: 9
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 6 authors...
5 CitationsSource
#1L. Wu (UT: University of Tennessee)H-Index: 5
#2Sean R. Agnew (UVA: University of Virginia)H-Index: 54
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 8 authors...
Abstract The effect of texture on the low-cycle fatigue behavior of a rolled magnesium alloy, AZ31B, was studied at room temperature. It is shown that the Coffin–Manson and Basquin relationships can be used to describe the fatigue resistance of the alloy. The alloy loaded along the rolling direction exhibits only slightly better low-cycle fatigue resistance than that loaded along the transverse direction, due to the in-plane texture symmetry. The in-plane cases exhibit better fatigue behavior th...
138 CitationsSource
#1L. Wu (UT: University of Tennessee)H-Index: 5
#2Sean R. Agnew (UVA: University of Virginia)H-Index: 54
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 8 authors...
Abstract A study of the internal strain (stress) evolution during cyclic deformation dominated by { 1 0 1 ¯ 2 } 〈 1 0 1 ¯ 1 〉 twinning and detwinning mechanisms within a magnesium alloy, ZK60A, was conducted using in situ neutron diffraction. It is shown that once the matrix grains twin, the (00.2) matrix and twin grains are relaxed relative to the neighbors. This load redistribution between the soft- and hard-grain orientations is a result of plastic anisotropy. The twins which formed during th...
214 CitationsSource
#1L. Wu (UT: University of Tennessee)H-Index: 5
#2A. Jain (UVA: University of Virginia)H-Index: 8
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 8 authors...
Abstract The twinning and detwinning behavior in a strongly textured magnesium alloy was investigated using in situ neutron diffraction during the cyclic deformation along the prior extrusion direction at the fully reversed total constant strain amplitude of 1.2% at room temperature. The initial preferred orientation places the c-axis in most grains perpendicular to the loading axis, and this favors extensive { 1 0 1 ¯ 2 } 〈 1 0 1 ¯ 1 〉 twinning under compressive loading. In contrast, the grains...
383 CitationsSource
#1L. Wu (UT: University of Tennessee)H-Index: 5
#2G.M. Stoica (UT: University of Tennessee)H-Index: 9
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 9 authors...
The fatigue behavior of magnesium-alloy, AZ31B, prestrained by equal-channel-angular pressing (ECAP) was studied as a function of the accumulated plastic-strain level and the orientation of the samples (along and perpendicular to the ECAP pressing direction). The material was processed via route BC, at 200 °C, for 1, 2, and 8 passes, with and without a back pressure (BP) applied on the billet during ECAP. The low-cycle fatigue behavior of the AZ31B alloy is shown to be anisotropic and texture de...
24 CitationsSource
#1L.J. Chen (SUT: Shenyang University of Technology)H-Index: 9
#2Chunyan Wang (SUT: Shenyang University of Technology)H-Index: 1
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 7 authors...
The low-cycle fatigue behavior of an as-extruded AM50 magnesium alloy has been investigated. The cyclic stress response of the alloy strongly depends on the imposed strain amplitude. It is also noted that at the higher total strain amplitudes, the alloy exhibits a pronounced anisotropic deformation behavior in the direction of tension and compression, where the width of the s-e hysteresis loop in the compressive direction is greater than that in the tensile direction. At the total strain amplitu...
64 CitationsSource
#1G.M. Stoica (UT: University of Tennessee)H-Index: 9
#2D.E. Fielden (UT: University of Tennessee)H-Index: 7
Last. Terence G. Langdon (SC: University of Southern California)H-Index: 139
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Four fundamental models, based on slip-line theory, are compared to experimental results obtained from deforming scribed billets in a single pass of equal-channel angular pressing (ECAP). Two ECAP die configurations, having sharp and round corners, are used to determine the experimental flow-line fields for Pb, pure Cu and pure Al billets. Two different types of deformation behavior are observed when using the die with a sharp-corner: (a) for the Cu and Al billets a gap develops at the outer cor...
31 CitationsSource
#1L. J. Chen (UT: University of Tennessee)H-Index: 3
#2C.Y. Ma (SUT: Shenyang University of Technology)H-Index: 1
Last. Terence G. Langdon (SC: University of Southern California)H-Index: 139
view all 6 authors...
The tensile properties and stress-controlled fatigue behavior of an unreinforced 6061 Al alloy and an Al2O3/6061 Al composite were investigated at room temperature after processing by equal-channel angular pressing (ECAP) for eight passes at a temperature of 260 °C. The results show the tensile and fatigue strength of the Al2O3/6061 Al composite are significantly enhanced by ECAP while the elongation to failure is lower than before ECAP. For the unreinforced 6061 Al alloy, both the tensile and f...
21 CitationsSource
#1Sean R. Agnew (UVA: University of Virginia)H-Index: 54
#2P. Mehrotra (UVA: University of Virginia)H-Index: 3
Last. Peter K. Liaw (UT: University of Tennessee)H-Index: 94
view all 5 authors...
Abstract Texture strongly impacts the plasticity of metals and the equal channel angular extrusion (ECAE) process has been demonstrated to induce unusual textures and enhance the room temperature ductility of magnesium alloys. This paper documents a wide range of textures that may be generated by ECAE of magnesium alloys. Considered broadly, the ECAE processing of magnesium alloys tends to produce 〈0 0 0 1〉 fiber textures. Unlike conventional rolling, which tends to produce 〈0 0 0 1〉 || normal d...
116 CitationsSource