Claudio Zambaldi

Max Planck Institute for Sustainable Materials | MPIE · Department of Microstructure Physics and Alloy Design

We present the orientation dependent indentation response of pure magnesium during single grain indentation. A conical indenter and maximum loads between 50 mN and 900 mN were employed. Indent topographies were acquired by confocal microscopy. The indents were also characterized by electron backscatter orientation microscopy for their microstructur...

Slip transmission across grain boundaries is an essential micromechanical processes during deformation of polycrystalline materials. Slip transmission processes can be characterized based on the geometrical arrangement of active slip systems in adjacent grains and the value of the critical resolved shear stress acting on the incoming and possible o...

The plastic deformation of lamellar microstructures composed of the two phases γ-TiAl and α2-Ti3Al is highly orientation dependent. In this paper we present a homogenized model that takes into account the micromechanical effect of the plate-like morphologies that are often observed in two-phase titanium aluminide alloys. The model is based on cryst...

This study reports on the anisotropic indentation response of alpha-titanium. Coarse-grained titanium was characterized by electron backscatter diffraction. Sphero-conical nanoindentation was performed for a number of different crystallographic orientations. The grain size was much larger than the size of the indents to ensure quasi-single-crystal...

Single crystals of c-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase gamma-a2-microstructures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of gamma-TiAl was studied by nanoindentation experiments in single-phase regions of these gamma-a2-microstructures. Th...

The influence of grain boundaries on plastic deformation was studied by carrying out nanoindentation near grain boundaries (GBs). Surface topographies of indentations near grain boundaries were characterized using atomic force microscopy (AFM) and compared to corresponding single crystal indent topographies collected from indentations in grain inte...

The Matlab toolbox STABiX provides a unique and simple way to analyse slip transmission in a bicrystal. Graphical User Interfaces (GUIs) are implemented in order to import EBSD results, and to represent and quantify grain boundary slip resistance. Key parameters, such as the number of phases, crystal structure (fcc, bcc, or hcp), and slip families...

Instrumented spherical indentation has been used to extract information on the deformation behaviour of (0001) oriented grains in commercial purity magnesium. Reproducible discontinuities were found in the loading and the unloading curves and these have been interpreted as the nucleation and growth of {101̄2} extension twins during loading and thei...

Study of Bi-Crystal Grain Boundary Deformation in Commercially Pure Tantalum.

The Matlab toolbox STABiX provides a unique and simple way to analyse slip transmission in a bicrystal. Graphical User Interfaces (GUIs) are implemented in order to import EBSD results, and to represent and quantify grain boundary slip resistance. Key parameters, such as the number of phases, crystal structure (fcc, bcc, or hcp), and slip families...

We present the orientation dependent indentation response of pure magnesium during single grain indentation. A conical indenter and maximum loads between 50 mN and 900 mN were employed. Indent topographies were acquired by confocal microscopy. The indents were also characterized by electron backscatter orientation microscopy for their microstructur...

The effect of temperature on the main deformation mechanisms of pure magnesium (Mg) was investigated using nanoindentation combined with atomic force microscopy, electron backscatter diffraction and finite element crystal plasticity simulations. While twinning is clearly apparent near the indents performed at room temperature, almost no twinning ac...

We present the orientation dependent indentation response of pure magnesium during single grain indentation. A conical indenter and maximum loads between 50 mN and 900 mN were employed. Indent topographies were acquired by confocal microscopy. The indents were also characterized by electron backscatter orientation microscopy for their microstructur...

Poster presented at "Indentation 2014" Conference in Strasbourg (France) (December 2014). Spherical indentation and crystal plasticity modeling near grain boundaries in alpha‐Ti.

The mechanical response of multiphase alloys is governed by the microscopic strain and stress partitioning behavior among microstructural constituents. However, due to limitations in the characterization of the partitioning that takes place at the submicron scale, microstructure optimization of such alloys is typically based on evaluating the avera...

Indentation in single grains of coarse grained pure magnesium with a 90° conical indenter (tip radius 1 μm) and 50 mN to 900 mN maximum loads. Topographies were characterized by confocal white light microscopy; the ND-IPF representations of the topographies and microstructures follow Zambaldi and Raabe (2010) Acta Mater, see http://czam.de/sx-inden...

We present a study about the dependence of the evolution of orientation patterns around nanoindents on the presence of a grain boundary. In prior work, the plasticity of single crystalline Ti-5Al-2.5Sn (wt%) near α-alloy has been quantified by a combination of crystal lattice orientation mapping, instrumented sphero-conical nanoindentation, and mea...

Analyzing spherical indentation of a bicrystal MATLAB GUI --> from EBSD to CPFEM

The reduced modulus, ER, of elastically anisotropic materials (Si, CaF2 and MgF2) was determined for sub-10 nm, several-10 nm and several-100 nm indentation depths, applying the Hertzian and Oliver–Pharr approaches. The ER values determined for Si(100), Si(111), CaF2(100) and MgF2(100) deforming at sub-10 nm indentations (i.e. 135 GPa, 177 GPa, 142...

Heterogeneous deformation, including local dislocation shear activity and lattice rotation, was analyzed in microstructure patches of polycrystalline commercial purity titanium specimens using three different experimental methods. The measurements were compared with crystal plasticity finite element simulations for the same region that incorporate...

The plastic deformation of lamellar microstructures composed of the two phases g-TiAl and a 2-Ti 3 Al is highly orientation dependent. In this paper we present a homogenized model that takes into account the micromechanical effect of the plate-like morphologies that are often observed in two-phase titanium aluminide alloys. The model is based on cr...

This study reports on the anisotropic indentation response of a-titanium. Coarse-grained titanium was characterized by electron backscatter diffraction. Sphero-conical nanoindentation was performed for a number of different crystallographic orientations. The grain size was much larger than the size of the indents to ensure quasi-single-crystal inde...

Local lattice rotations and in-grain orientation gradients at κ precipitates in matrix grains with orientations near the 45° rotated cube {001}〈110〉 (RC) and the γ-fiber components {111}〈112〉 were investigated in a Fe3Al alloy warm-rolled to reductions of between 10% and 60%. Near-RC grains showed larger local lattice rotations at precipitates than...

Single-crystals of γ-TiAl cannot be grown for the compositions present inside the two-phase γ/α2-microstructures that show good mechanical properties. Therefore the single crystal constitutive behaviour of γ-TiAl was studied by nanoindentation experiments in single phase regions of these microstructures. The experiments were extensively characteriz...

Single crystals of c-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase c=a 2-microstruc-tures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of c-TiAl was studied by nanoindentation experiments in single-phase regions of these c=a 2-microstructures. The experim...

Single crystals of c-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase c=a 2-microstruc-tures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of c-TiAl was studied by nanoindentation experiments in single-phase regions of these c=a 2-microstructures. The experim...

The plastic deformation of lamellar microstructures composed of the two phases g-TiAl and a 2-Ti 3 Al is highly orientation dependent. In this paper we present a homogenized model that takes into account the micromechanical effect of the plate-like morphologies that are often observed in two-phase titanium aluminide alloys. The model is based on cr...

Single crystals of c-TiAl cannot be grown in the near-stoichiometric compositions that are present inside two-phase c=a 2-microstruc-tures with attractive mechanical properties. Therefore, the single-crystal constitutive behavior of c-TiAl was studied by nanoindentation experiments in single-phase regions of these c=a 2-microstructures. The experim...

A new approach to resolve the slight tetragonality of L10-ordered γ-TiAl by electron backscatter diffraction (EBSD) is presented. The phase has a c/a ratio of only about 2% larger than unity. The corresponding EBSD patterns therefore exhibit cubic pseudosymmetry. As a consequence, different order variants cannot be easily distinguished on the basis...

This study presents crystal-plasticity finite-element calculations of room temperature deformation of a single-crystal nickel-base superalloy and simulation results on the microstructural development during subsequent recrystallization. The predictions are compared to corresponding experiments. Single-crystalline material is deformed by Brinell-typ...