Strain rate sensitivity of the flow stress in a Ti-Al alloy: Analysis of the anomalous strengthening effect
- Univ. of Neuchatel (Switzerland). Inst. of Structural Metallurgy
An analysis has been made of the mechanisms controlling the strain rate dependence of the flow stress as a function of temperature in a Ti-Al alloy, based on the dislocation configurations observed together with the activation volumes measured at each temperature. At low temperatures (20--200 C), the low values of activation volume measured and their independence on strain have confirmed that a Peierls lattice friction mechanism controls the mobility of screw segments of either ordinary or superdislocations. At the higher temperatures (500--700 C) a climbing process of ordinary 1/2<110> dislocation segments with variable length is responsible for the slightly strain dependent activation volumes measured. The strongly strain dependent activation volumes obtained between 400--450 C has confirmed that the mechanism responsible for the anomalous peak in flow stress is produced by a jog dragging process as an increased density of jogs is created with increasing temperature, due to the increasing number of forest cutting events between ordinary 1/2<110> dislocations.
- OSTI ID:
- 7104682
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 31:6; ISSN SCRMEX; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
FLOW STRESS
INTERMETALLIC COMPOUNDS
LINE DEFECTS
MECHANICAL PROPERTIES
STRESSES
TEMPERATURE DEPENDENCE
TITANIUM ALLOYS
TITANIUM BASE ALLOYS