EFFECT OF TEST TEMPERATURE ON DEFORMATION MECHANISM OF Ti3Al-Nb ALLOY
来源期刊：中国有色金属学报(英文版)1997年第2期
论文作者：Wu Ying Liang Wei Cui Yuexian Li Daoming Yang Dezhuang
文章页码：77 - 82
Key words：Ti 3Al-Nb alloy; tensile deformation; dislocation; slip system
Abstract: Dislocation types and slip systems of the α 2 phase(DO 19) in a Ti 24Al 14Nb 3V 0.5Mo(mole percent) alloy tensioned in the temperature range from room temperature to 700 ℃ were analyzed in accordance with the g·b=0 invisibility criterion in an H 800 TEM equipped with a side entry gonimeter stage capable of ±45° tilting on the X or Y axis operating under two beam conditions. The results indicate that a type(b=1/6〈1120〉) dislocations can form a considerable amount of subgrain boundaries and hexagonal dislocation networks on basal planes {0001}; a[WT5”BZ] type edge dislocations and a few of c type(b=1/3〈0003〉)dislocations on prismatic planes {1010} are activated by tensile deformation at room temperature; a type dislocations are activated on prismatic planes by tensile deformation at 300, 500 and 600 ℃. No c+a/2 type dislocation pairs are found in specimens deformed at temperatures below 600 ℃; the majority of slip systems activated at 700 ℃ are a type dislocations on prismatic and basal planes, and a few c+a/2 type dislocation pairs on pyramidal planes {0221} are found. No twinning deformations are found in specimens deformed at any temperature. With increasing test temperature, straight dislocations gradually transform into curved dislocations and cross slips are strengthened. However, networks of dislocations apparently decrease and the dislocations tend toward screw orientations.
