Project Themis Metal Deformation Processing.
Annual rept. no. 5, 1 Sep 72-31 Dec 73,
KENTUCKY UNIV LEXINGTON
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A new analytical approach was developed for establishing the local stress state and temperature including regions near the surface in axisymmetric extrusions. Also a numerical method finite differences for solving the plasticity equations and thereby predicting the flow lines has been developed. The plastic deformation kinetics derived from hot extrusion tests on Ti-50A and Ti-5Al-2.5 Sn are in good accord with those for the high temperature deformation of these materials in simple tension or compression and it was deduced that the rate-controlling mechanism is glide and climb in Ti-50A and viscous glide in Ti-5Al-2.5 Sn. Further, the change from the single maximum type of visioplasticity pattern to the double maximum type appears to be governed mainly by the plastic flow behavior of the material. Friction studies employing the ring forging test indicate that for effective lubrication during the hot working of titanium alloys the ratio of viscosity eta of a glass lubricant to the flow stress sigma should be in the range 0.0001 etasigma 0.01 poisedynesq cm at interface velocities of 0.5 - 1.0 in.min. Modified author abstract
- Metallurgy and Metallography