X-ray Peak Profile Analysis on the Microstructure of Al-5.9%Mg-0.3%Sc-0.18%Zr Alloy Deformed by High Pressure Torsion Straining

The microstructure of plastically deformed Al-5.9%Mg-0.3%Sc-0.18%Zr alloy has been investigated. The severe plastic deformation has been performed by high pressure torsion straining (HPT) up to 15 revolutions at room temperature. The microstructure as a function of the number of revolutions is studied by X-ray diffraction peak profile analysis. It is concluded that the HPT technique results in nanostructure even after 0.5 turn with very high dislocation density. The crystallite size decreases and the dislocation density increases with the number of revolutions, however, after five turns they go into saturation. The edge and the dipole character of the dislocation structure becomes stronger with the increase of the number of revolutions. The value of the crystallite size determined by X-ray peak profile analysis is a bit smaller than the grain size obtained by transmission electron microscopy (TEM)

Platform Competition with Intra-Group Externalities

In this article we analyze asymmetric two-sided markets. Two types of agents are assumed to interact with each other and we assume that agents of one type derive utility from inter-group interactions, while the other type of agents benefit from intra-group rather than from inter-group interactions as it is assumed in the standard symmetric two-sided markets model. First, we consider a monopoly platform, then we analyze competing platforms, both with single-homing and multi-homing abilities