Gerhard Sauthoff(Max-Planck-Institut fur Eisenforschung GmbH.
,
D-40074 Dusseldorf
,
Germany)
金属学报(英文版)
Intermetallics for structural applications at high temperatures must show a sufficient high temperature strength which is controlled by creep processes. In the first section the creep behaviour of single-phase intermetallic alloys is overviewed with respect to stress and temperature dependence and effects of composition and microstructure. It is shown in particular that creep deformation is controlled by diffusion. The second section refers to multiphase intermetallic alloys, and both particulate and non-particulate alloys are regarded. Data are presented for single-phase and multiphase alloys based on B2 phases and lesscommon phases and the consequences of diffusion control for alloy design are discussed.
关键词:
:creep
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WR. Chen
,
J.Triantafillou
,
J. Beddoes and L. Zhao(Dept. of Mech. & Aero. Eng.
,
Carleton University
,
Ottawa
,
Canada Structures
,
Materials & Propulsion Laboratory
,
National Research Council
,
Ottawa
,
Canada Manuscript received 26 August 1996)
金属学报(英文版)
Creep of a polycrystalline near γ-TiAl alloy in two fully lamellar conditions is presented. A lamellar structure with fine interface spacing and planar grain boundaries provides improved creep resistance. The lamellar structure with wide interface spacing and interlocked grain boundaries has <1/2 the creep life, five times the minimum strain rate and greater tertiary strain.Creep strain is accommodated by dislocation motion in soft grains, but the strain rate is controlled by hard grains. The resistance to fracture is controlled by the grain boundary morphology, with planar boundaries causing intergranular fracture.To maximize the creep resistance of near γ-TiAl with a lamellar microstructure requires narrow lamellar interface spacing and interlocked lamellae along grain boundaries.
关键词:
:creep
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