The Flexural Strength and Fracture Toughness of TC4-Based Laminated Composites Reinforced with Ti Aluminide and Carbide
TiC–Ti–Al mixed powders and TC4 titanium alloy foils were overlapped layer-by-layer in the graphite die. The TC4-based laminated composite sheets reinforced by Ti aluminide and carbide were successfully fabricated via spark plasma sintering (SPS) at 1100 °C with a well-bonded interface. The composite layers were mainly composed of TiAl, Ti3Al, Ti2AlC, and Ti3AlC2 phases. The carbides particles distributed in the matrix played an important role in the deflection of cracks and the passivation of microcracks. TC4 titanium alloy layers had an obvious effect on the stress distribution during the loading process, and provided an energy dissipation mechanism, which could improve the mechanical properties of the laminated composite sheets obviously. When the theoretical amount of Ti2AlC was 20 wt %, the flexural strength and fracture toughness of the laminated composite sheets reached the maximum value in the arrester direction, which were 1428.79 MPa and 64.08 MPa·m1/2, respectively.
A new method to texture dense Mn+1AXn ceramics by spark plasma deformation
Abstract This work explored a new method to texture M n +1 AX n phases by deforming discs of dense ceramics Maxthal 211® (nominally Ti 2 AlC) and Maxthal 312® (nominally Ti 3 SiC 2 ) in a spark plasma facility. The disc diameter increased by 40% without crack formation. After deformation, the MAX grains exhibited clear preferential crystallographic orientation, whereby the c -axis was aligned to the compression direction. The fracture toughness increased both parallel and perpendicular to the textured top surface compared with the as-sintered materials. The onset of plastic deformation was observed near the brittle-to-plastic transformation temperature, a fact that could be associated with the change in elastic response.
Recovering the frontier state : war, ethnicity, and state in Afghanistan
Chapter 1 Table of Contents Chapter 2 1 Introduction Chapter 3 2 Ethnicity, Political Power, and Fragmentation Chapter 4 3 Rise of the Taliban and Civil War Chapter 5 4 The United States and War on Terrorism Chapter 6 5 Restructuring the Afghan State Chapter 7 6 Political Economy of Drugs and Warlordism Chapter 8 7 Afghanistan and Neighboring States Chapter 9 8 Conclusion Chapter 10 Bibliography