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Materials Science and Engineering

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Selected Works

1998

Articles 1 - 2 of 2

Full-Text Articles in Chemistry

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part Ii. Microstructure And Mechanism, Xiaoli Tan, H. Guo, H. Gu, C. Laird, N. D. H. Monroe Feb 1998

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part Ii. Microstructure And Mechanism, Xiaoli Tan, H. Guo, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Strain-controlled cyclic tests have been conducted on high-purity titanium single crystals with different orientations. The fatigue mechanisms of the titanium crystals were studied by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It was found that single slip lines, wavy slip lines, double slip lines, twins, and associated slip lines occurred in differently oriented single crystals. A new type of fractographic morphology, parallel traces, was observed. Dislocation patterns and cyclic twins, as well as the mechanical response, were analyzed. The dependence of the deformation mechanisms on the orientations of the single crystals is discussed.


Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part I. Orientation Dependence Of Stress-Strain Response, Xiaoli Tan, H. Gu, C. Laird, N. D. H. Monroe Feb 1998

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part I. Orientation Dependence Of Stress-Strain Response, Xiaoli Tan, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Randomly oriented single crystals of high-purity titanium were prepared by strain annealing and were subjected to multiple-step fatigue testing under strain-controlled conditions, in order to determine their cyclic stress-strain curves (CSSCs). These were found to fall into three groups, depending on orientation and the extent of slip and twinning. For those crystals oriented for single prismatic slip, a plateau was observed in the CSSCs, persistent slip bands (PSBs) occurred, and the plateau stress was 38 MPa. In a second group, oriented for prismatic slip but for which cross-slip and twinning was favored, the plateau was suppressed and the flow stresses …