Cast iron is used in various engineering and construction applications due to its excellent casting properties and low cost. One example of its use is in the automotive industry, where many of the load-bearing components of the engine and exhaust system of heavy trucks are manufactured in cast iron. Recent developments in engine design strive towards improving efficiency and power density and, at the same time, reducing emissions of greenhouse gases. Such improvements will inevitably lead to an increase in combustion pressure and temperature in the engine, resulting in increased stress on the load-bearing components. There is, therefore, a strong interest in developing novel materials to enhance the performance of these engine components. The first step in doing so is to gain better insight into the deformation, damage, and failure mechanisms at play during the mechanical loading of cast iron.

We have performed in situ imaging using X-ray tomography and 3DXRD (both line beam and scanning modalities) of cast iron samples during tensile loading. From the tomography data, it is possible to map out the primary phases in the sample and segment the evolution of several damage mechanisms (crack growth, delamination, etc.). Determining the macroscopic strain field through digital volume correlation (DVC) is also possible. 3DXRD provides information on the spatial position, orientation, and stress tensor of each individual (iron) grain in the sample. Combining such microscale information with the macroscale strain field computed using DVC makes it possible to construct spatially resolved stress-strain curves from different regions inside the sample. This will be extremely useful information, for example, when developing crystal plasticity models or other micro-mechanical models where experimental data on grain orientations and stress states are necessary for accurately calibrating parameters to real materials.