Korngrenzengleiten und Wechselwirkungsmechanismen mit klassischen Verformungsprozessen beim Kriechen feinkörniger -TiAl-Legierungen mit Duplexgefüge unter ein- und mehrachsiger Beanspruchung

• Applicant: Professor Dr.-Ing. Gunther Eggeler
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2009 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 153826398

• Final Report Year: 2015

Final Report Abstract

In the present work, the microstructural evolution during tensile creep of a modern hotextruded gamma-TiA1 alloy with a fine-grained duplex microstructure was studied. From the results obtained, the following conclusions can be drawn: 1) Creep tests conducted with the same parameters yield identical creep curves. 2) The lamellar colonies are not stable and show different degradation morphologies. Coarsening and fragmentation of lamellae are frequently observed. 3) Continuous small scale dynamic recrystallization events associated with the formation of fine recrystallized gamma and alpha2 grains, mainly at colony boundaries, lead to a loss in creep strength. 4) Fine grains along colony boundaries promote grain boundary sliding, which probably leads to local cavitation along adjacent colonies. 5) EBSD results suggest that grain boundary sliding is the major deformation mechanism in the regions with fine grains.

Publications

• Analysis of local microstructure after shear creep deformation of a fine-grained duplex y-TiAl alloy, Acta Materialia, 58 (2010) pp.6431-5443
  D. Peter, G.B. Viswanathan, A. Dlouhy, G. Eggeler
  
• Microstructural characterization of lamellar features in TiAl by FIB imaging, Advanced Engineering Materials, 12 (2010) pp. 447-452
  D. Peter, G. Eggeler, M. F.-X. Wagner
  
• High temperature test rig for inert atmosphere miniature specimen creep testing, Matwiss. u. Werkstofftechn., 42 (2011) pp. 493-499
  D. Peter, F. Otto, T. Depka, P. Nörtershäuser, G. Eggeler