High temperature dynamic yielding in metastable Ti-6.8Mo-4.5Fe-1.5Al

被引:142
作者
Philippart, I [1 ]
Rack, HJ [1 ]
机构
[1] Clemson Univ, Sch Chem & Mat Engn, Dept Ceram & Mat Engn, Clemson, SC 29634 USA
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 1998年 / 243卷 / 1-2期
关键词
discontinuous yield behavior; high temperature dynamic yielding; strain rate;
D O I
10.1016/S0921-5093(97)00800-9
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
The discontinuous yield behavior of TIMETAL LCB (Ti-6.8Mo-4.5Fe-1.5AI), a prototypic metastable beta titanium alloy, has been examined between 840 and 1290 degrees C over strain rates of 2 x 10(-4)-1 s(-1). These studies have shown that the magnitude of the discontinuous yield drop exhibits, at constant strain rate, a broad maximum with increasing test temperature, the temperature of this maximum increasing with increasing strain rate. Incremental straining experiments indicate that the discontinuous yield phenomena observed is associated with mobile dislocation generation from grain boundaries, plastic deformation then spreading inwards towards the grain interior with increasing strain. These observations are consistent with the dynamic approach to Johnston and Gilman's dynamic yield theory-that grain boundaries act as sources for mobile dislocation generation. Activation analysis further suggests that the temperature dependence of the discontinuous yield drop is related to unlocking of dislocation sources through localized dislocation climb, boundary migration and/or solute rearrangement. (C) 1998 Elsevier Science S.A. All rights reserved.
引用
收藏
页码:196 / 200
页数:5
相关论文
共 15 条
[1]   THE EFFECT OF VOLUME PER CENT OF PHASES ON THE HIGH-TEMPERATURE TENSILE DEFORMATION OF 2-PHASE TI-MN ALLOYS [J].
ANKEM, S ;
SHYUE, JG ;
VIJAYSHANKAR, MN ;
ARSENAULT, RJ .
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 1989, 111 :51-61
[2]  
COURTNEY TH, 1992, MECH BEHAV MAT, pCH3
[3]   SUPERPLASTICITY IN LARGE GRAINED MATERIALS [J].
GRIFFITHS, P ;
HAMMOND, C .
ACTA METALLURGICA, 1972, 20 (07) :935-+
[4]   DISLOCATION VELOCITIES, DISLOCATION DENSITIES, AND PLASTIC FLOW IN LITHIUM FLUORIDE CRYSTALS [J].
JOHNSTON, WG ;
GILMAN, JJ .
JOURNAL OF APPLIED PHYSICS, 1959, 30 (02) :129-144
[5]   ANNEAL HARDENING AND FLOW SOFTENING IN BETA-ZIRCONIUM-NIOBIUM ALLOYS [J].
JONAS, JJ ;
HERITIER, B ;
LUTON, MJ .
METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 1979, 10 (05) :611-620
[6]  
Long M., 1996, TITANIUM 1995 SCI TE, P316
[7]   POLYCRYSTALLINE STRENGTHENING [J].
MARGOLIN, H ;
STANESCU, MS .
ACTA METALLURGICA, 1975, 23 (12) :1411-1418
[8]   HIGH-TEMPERATURE DEFORMATION OF POLYCRYSTALLINE BETA-TITANIUM [J].
OIKAWA, H ;
NISHIMURA, K ;
CUI, MX .
SCRIPTA METALLURGICA, 1985, 19 (07) :825-828
[9]  
PHILIPPART I, 1995, THESIS CLEMSON U CLE
[10]   GRAIN-BOUNDARY EMBRITTLEMENT IN A BETA-TITANIUM ALLOY [J].
RACK, HJ .
METALLURGICAL TRANSACTIONS, 1975, A 6 (04) :947-949