Characterization on microstructure of interface and failure analysis of SiC fiber reinforced Ti-17 composites under tension load

From IOP Publishing via Jisc Publications RouterHistory: ppub 2021-05, open-access 2021-05-01Publication status: PublishedAbstract: In this study, the ultimate tensile strength of unidirectional SiC-fiber/Ti-17 composites was measured in the as-produced condition at room temperature. Fracture and interfacial reaction zone was characterized by using laser confocal microscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy. Elemental distribution maps of the interfacial reaction layer and titanium matrix were quantitatively examined by electron probe micro-analyzer (EPMA). Micromechanical properties of SiC fiber and titanium matrix was inspected by Nano-indentation. The Fracture failure mechanisms was show that the key microstructural parameters which dominate damage initiation, damage growth and fracture behavior of the composites were explained in detail

Process of disordering and grain refinement in Ni3Al by high-pressure torsion

豊橋技術科学大

Mechanical and Microstructural Characterization of Percussive Arc Welded Hyper-Pins for Titanium to Composite Metal Joining

The manufacture of Ti- composite hyper-joints for aerospace applications requires arrays of pins to be attached to a metal component’s surface. Here, the feasibility of using percussive arc micro-welding for this purpose has been explored, applied to dissimilar Ti alloys, to allow advantage to be taken of tailored pin properties. To simulate the process, Timetal21s wire pins were welded to a Ti-6Al-4V baseplate under optimized parameters. Analysis of the welds indicated the presence of martensitic microstructures and chemical inhomogeneity in the melt pool, as a result of the rapid weld cycle (5 ms). The performance of the welded pins was assessed by a micro-tensile and a pin shear/bend test, assisted by FE modeling.</jats:p

An investigation of diffusion-mediated cyclic coarsening and reversal coarsening in an advanced Ni-based superalloy

AbstractThe anomalous cyclic coarsening behaviour of γ′ precipitates after ageing at 1073 K has been investigated for the low misfit commercial powder metallurgy (PM) Ni-based superalloy RR1000. Using scanning transmission electron microscope (STEM) imaging combined with absorption-corrected energy-dispersive X-ray (EDX) spectroscopy, the elemental segregation as a function of coarsening behaviour has been experimentally observed for secondary γ′ precipitates. Elemental EDX spectrum imaging has revealed nanoscale enrichment of Co and Cr and a depletion of Al and Ti within the γ matrix close to the γ-γʹ interface. Our experimental results, coupled with complementary modelling and synchrotron X-ray diffraction analysis, demonstrate the importance of elastic strain energy resulting from local compositional variations for influencing precipitate morphology. In particular, elemental inhomogeneities, as a result of complex diffusive interactions within both matrix and precipitates, play a crucial role in determining the rate of coarsening. Our findings provide important new evidence for understanding the microstructural evolution observed for advanced superalloys when they are exposed to different heat treatment regimes