Electron back scattered diffraction characterization of thermomechanical fatigue crack propagation of a near α titanium alloy Timetal 834. (January 2015)

• Record Type: Journal Article
• Authors: Prasad, Kartik; Karamched, Phani S.; Bhattacharjee, A.; Kumar, Vikas; Bhanu Sankara Rao, K.; Sundararaman, M.
• Is Part Of: Materials & design. Volume 65(2015:Jan.)
• Page Start: 297
• Page End: 311
• Publication Date: 2015-01
• Subjects: Schmid factor -- fracture -- crystal plasticity -- slip -- microstructure; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2014.09.006
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract : Graphical abstract: Highlights: The alloy shows lower crack growth rate under IP-TMFCG loading. Larger plastic zone size at the crack tip was observed under IP-TMFCG loading. Primary crack tends to form branches when it enters prismatic slip oriented grain. Abstract: Fatigue crack growth (FCG) mechanisms have been studied in light of the interaction of a propagating crack with local crystallographic orientations of primary alpha (αP ) and secondary alpha (αS ) colonies in a near α Timetal 834 Ti-alloy under thermomechanical fatigue (TMF) loading using electron backscattered diffraction (EBSD). FCG testing at in-phase (IP) and out-of-phase (OP) TMF loading have been carried out at two temperature intervals 300 °C ↔ 450 °C and 450 °C ↔ 600 °C. EBSD analysis and microhardness measurements have confirmed that larger cyclic plastic zone size at the crack tip leads to lower crack propagation under IP-TMFCG loading as compared to OP-TMFCG loading. EBSD analysis has also confirmed that crack dissipates more energy to propagate when it passes from a soft grain oriented with its c -axis normal to the loading direction and encounters a hard grain with its c -axis parallel with the loading direction.