Understanding Temperature and Microstructure Effects on Damage Accumulation in Ti Alloys Under Sustained-Peak Low-Cycle Fatigue (SPLCF)
Abstract
Slip activity in dwell fatigued Ti-6Al-2Sn-4Zr-2Mo, and its relation to the microstructure, was investigated using digital image correlation and electron backscatter diffraction at room temperature, 120 deg C, and 200 deg C to span a range of dwell sensitivities. The length, orientation, and Schmid factors of the grains through which slip traces traversed, and the active slip family of each trace, were examined to identify critical grain characteristics in the percolation of long-range slip on the specimen surface. It was found that slip accumulated more rapidly and in greater amounts at temperatures that exhibit dwell sensitivity (room temperature and 120 deg C) versus not (200 deg C). At all temperatures, plasticity occurred primarily by long-range basal slip through co-located grains with a high basal Schmid factor. These findings indicate that microstructure, particularly the distribution of basally soft grains, dictates the location of slip accumulation regardless of temperature. The grains exhibiting this type of deformation were sub-features of microtextured regions defined using current methods, indicating that these approaches are not sufficient indicators of whether a microtextured region will develop long-range slip. The observed slip activity suggests the necessity of grain interconnectivity and a smaller spread in c-axes when identifying the boundaries of a microtextured region.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 08, 2020
- Accession Number
- AD1110661
Entities
People
- James Barber
Organizations
- University of Michigan