Parallel Tubular Channel Angular Pressing (PTCAP) process is a novel recently developed severe plastic deformation (SPD) method for producing ultrafine grained (UFG) and nanograined (NG) tubular specimens with excellent mechanical and physical properties. This process has several advantageous compared to its TCAP counterparts. In this paper, a fine grained AZ91 tube was fabricated via multi pas...

Friction stir processing (FSP) has been considered as a novel technique to refine the grain size and homogenize the microstructure of metallic materials. In this study, two-pass FSP was conducted under water to enhance the cooling rate during processing, and an AZ61 magnesium alloy with fine-grained and homogeneous microstructure was prepared through this method. Compared to the as-cast materia...

Introduction: The CONCORDIA micrometeorite collection recovered from central Antarctic snow contains fluffy, fragile particles [1] among which we identified some UltraCarbonaceous Antarctic Micrometeorites (UCAMMs) [2, 3]. UCAMMs are dominated by up to ~ 80 vol% of carbonaceous material that contains small and complex mineral assemblages [2-4]. Their structure and chemical compositions are remi...