Crystal Plasticity and Quasi-Cleavage Facet Formation During Fatigue Loading
Sub-surface quasi-cleavage facets are often found at fatigue crack initiation sites in α/β and near a titanium alloys. Their orientation,usually near perpendicular to the principal tensile stress axis,fails to comply with traditional models for fatigue initiation. Their scale is dependent on the local microstructure. In Ti 6/4 for example,individual facets are formed within the bounds of primary a grains, although clusters of facets are commonly formed thus identifying the region of early propagation. Stress redistribution between weak and strong regions has been invoked as a mechanism for facet formation. Due to the limited available slip systems in the α phase,on the crystallographic scale such heterogeneous properties could be induced by neighbouring grains of different orientation. In particular, the orientation of basal planes relative to the tensile stress axis appears to be a critical factor. This paper describes a number of key morphological features generated under fatigue loading. Unique evidence is also presented,gained from TEM inspections beneath facets,for the specific active slip systems that precede facet formation and crack development. The findings directly support previously proposed models for facet formation.
Fatigue facet slip dislocation
Martin R. Bache Cameron Pleydell-Pearce Rengen Ding Ian. P. Jones
Materials Research Centre, College of Engineering, Szvansea University, Singleton Park ,Swansea, SA2 Materials Research Centre, College of Engineering, Szvansea University, Singleton Park , Swansea, SA Department of Metallurgy,University of Birmingham,Edgbaston,Birmingham. B15 2TT,United Kingdom
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1152-1155
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）