The Role of Microtexture on Fatigue Lifetime Variability and Crack Initiation Mechanisms
Commercial titanium alloys have demonstrated a fatigue lifetime debit in material that contains microtextured regions,as compared to material that has been processed to reduce microtexture. This result has generated incentive to identify the effectiveness of various thermomechanical processing steps to remove microtexture and to determine the fatigue crack initiation mechanisms in these microtextured regions. To quantify the efficacy of microtexture reduction on the fatigue behavior of alpha+beta titanium alloys, three different microstructural conditions of Ti-6A1-4V have been produced via distinct thermomechanical processing routes:an equiaxed alpha microstructure containing microtexture,an equiaxed alpha microstructure free of microtexture, and a beta annealed structure. The impact of sample orientation on fatigue behavior was examined by testing specimens along three different loading directions relative to the original plate reference frame: the rolling direction, the transverse direction, and 45° from the rolling direction for each of these microstructural conditions. The mechanisms of fatigue crack initiation are discussed with regard to microstructural condition (processing history) and sample orientation. The distributions of fatigue lifetimes are characterized based on processing condition to determine if the presence of microtexture significantly impacts fatigue lifetime variability.
Microtexture thermomechanical processing fatigue crack initiation fatigue lifetime distribution
Christopher J. Szczepanski S. Lee Semiatin James M. Larsen
US Air Force Research Laboratory ,Wright-Patterson Air Force Base,OH 45433 USA
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1281-1284
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）