Accessing Colony Boundary Strengthening of Fully Lamellar TiAl Alloys via Micromechanical Modeling
Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht, Max-Planck-str. 1, 21502 Geesthacht, Germany
Chair of Solid Mechanics, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany
Author to whom correspondence should be addressed.
Received: 26 June 2017 / Revised: 27 July 2017 / Accepted: 31 July 2017 / Published: 3 August 2017
In this article, we present a strategy to decouple the relative influences of colony, domain and lamella boundary strengthening in fully lamellar titanium aluminide alloys, using a physics-based crystal plasticity modeling strategy. While lamella and domain boundary strengthening can be isolated in experiments using polysynthetically twinned crystals or mircomechanical testing, colony boundary strengthening can only be investigated in specimens in which all three strengthening mechanisms act simultaneously. Thus, isolating the colony boundary strengthening Hall–Petch coefficient
experimentally requires a sufficient number of specimens with different colony sizes
but constant lamella thickness
and domain size
, difficult to produce even with sophisticated alloying techniques. The here presented crystal plasticity model enables identification of the colony boundary strengthening coefficient
as a function of lamella thickness
. The constitutive description is based on the model of a polysynthetically twinned crystal which is adopted to a representative volume element of a fully lamellar microstructure. In order to capture the micro yield and subsequent micro hardening in weakly oriented colonies prior to macroscopic yield, the hardening relations of the adopted model are revised and calibrated against experiments with polysynthetically twinned crystals for plastic strains up to 15%.
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MDPI and ACS Style
Schnabel, J.E.; Bargmann, S. Accessing Colony Boundary Strengthening of Fully Lamellar TiAl Alloys via Micromechanical Modeling. Materials 2017, 10, 896.
Schnabel JE, Bargmann S. Accessing Colony Boundary Strengthening of Fully Lamellar TiAl Alloys via Micromechanical Modeling. Materials. 2017; 10(8):896.
Schnabel, Jan E.; Bargmann, Swantje. 2017. "Accessing Colony Boundary Strengthening of Fully Lamellar TiAl Alloys via Micromechanical Modeling." Materials 10, no. 8: 896.
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