刘杰
,
薛祥义
,
杨劼人
,
寇宏超
,
李金山
,
胡锐
稀有金属材料与工程
以Ti-48A1-2Cr-2Nb(at％)合金为研究对象,通过热处理获得近片层和全片层两种显微组织,并在800℃空气条件下,进行了100 h的抗氧化性实验.利用OM、SEM、TEM、XRD和EDS对试样的微观结构、相组成及微区成分进行了分析.恒温氧化动力学结果表明:在800℃空气条件下,对于近片层和全片层两种TiAl合金组织,其恒温氧化动力学曲线符合近抛物线规律,且近片层组织合金的抗氧化性能优于全片层组织.基于氧化动力学曲线、组织结构、氧化膜结构、氧化表面形貌分析,表明TiAl合金的片层组织结构对其氧化行为具有不可忽视的影响.
关键词:
TiAl合金
,
显微组织
,
片层结构
,
氧化行为
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
,
null
,
null
,
null
,
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范学燚
,
王亮
,
苏彦庆
,
骆良顺
,
贾丽敏
,
徐达鸣
,
郭景杰
稀有金属
基于多晶材料球形晶粒的假设合金相理论的基础上,建立了的计算两相片状组织表观值与真实值定量关系的数学模型.结果表明,对于多数多晶材料其晶粒尺寸远大于片间距,片间距的平均表观值与真实值的比可以由修正系数k表征.片间距与晶粒尺寸比值从0.05减小到0.0001,k从1.5391增加到1.5707,k值逐渐接近于k/2.当片间距与晶粒尺寸的比值小于0.001时,可以认为k为常数k/2.本模型比传统方法在得到真实片间距过程中减少了工作量.
关键词:
层片间距
,
定量体视学
,
片状组织
,
数学模型
