Hot-Deformation Mechanisms in Near-Alpha Titanium Alloy 685

Abstract

Mechanical processing is an important step in the manufacture of engineering components; with improved instrumentation of these processing techniques, it has become easier to execute complicated shape making processes with the utmost precision. However, sophistication in the instrumentation alone cannot ensure a defect-free, metallurgically sound product and control of the product's microstructure during mechanical processing is required. Workability is greatly influenced by the temperature of deformation, strain rate, and state-of-stress. There are several specialized tests to measure hot workability, including the axisymmetric hot-compression test.2 The stress-state during the test is very similar to many bulk deformation processes. The problems of necking (e.g., tension) or material reorientation (e.g., torsion) are not encountered, therefore, deformation to a very large extent is possible before fracture. The extent of barreling can be minimized by the application of lubricants between specimen ends and compression platens. Thus, the hot-compression test is unique for workability evaluation.