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Abstract: The purpose of the present work is to build the relationship between impression creep and conventional uni-axial tensile creep in determining crystallographic creep parameters for face centered cubic (FCC) nickel-based single crystal superalloys. To this aim, the impression creep performed on [001]-, [011]-, and [111]-oriented nickel-based single crystal superalloys were respectively investigated and the data was compared with those obtained with uni-axial tensile creep counterparts. It shows that the determination of crystallographic creep stress exponent is independent of crystallographic orientations, and the results agree reasonably well between impression creep and uni-axial tensile creep. However, some reveres dependence of crystallographic orientation was observed between impression creep and uni-axial tensile creep, such as the steady-state punch velocity for impression creep and steady-state elongation rate for uni-axial tensile creep, and this induced different stress conversion factors among different crystallographic orientations. [Copyright &y& Elsevier]

This paper investigated the relationship between crystallographic-orientation and micro-cracks of Ti-47Al-2Cr-2Nb alloy. Results show that the crystallographic-orientation is adverse in the nearly γ microstructure and becomes advantageous in the fully lamellar microstructure. Therefore, micro-cracks largely generate in the nearly γ microstructure and much decrease in the fully lamellar microstructure. [ABSTRACT FROM AUTHOR]

Abstract A novel approach of liquid deposition method (LDM) together with selective laser melting (SLM) have been used to process Ti-43.5Al-6.5Nb-2Cr-0.5B/reduced graphene oxide (RGO) metal matrix composites (MMCs). The grain size, crystallography texture, phases composition and compressive properties can be tailored by controlling the RGO content in Ti-43.5Al-6.5Nb-2Cr-0.5B/RGO MMCs. Due to the combined effects of grain refinement mechanism and special phases composition, the SLM-processed TiAl/RGO parts exhibit the superior compressive strength of 1546.88 MPa and strain of 5.34%, as compare to the unreinforced Ti-43.5Al-6.5Nb-2Cr-0.5B counterpart. These results shed new insights in the innovation of design novel TiAl/RGO composites for SLM. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

The surface slip deformation characteristics around two different patterns of film cooling holes in perforated plates were investigated by room-temperature tensile testing. An ARAMIS system was employed to observe the strain distribution on the sample surface. The development of slip traces and the microstructure after fracture of the specimens were analyzed by optical microscope (OM) and scanning electron microscopy (SEM), respectively. The maximum surface strain of the specimens with a triangular penetration pattern measured by the ARAMIS system was found to be larger than that of the perforated square-patterned specimens at both the yield point and when approaching fracture. However, specimens with a triangular penetration pattern have a greater yield strength and ultimate tensile strength than the specimens with a square penetration pattern because the cross-cleavage fracture of the specimen with the square penetration pattern leads to larger damage than the single-slip deformation fracture of the specimen with the triangular penetration pattern. Octahedral slip systems of the two kinds of specimens were activated in the same slip system, and the slip band observed in the experiment is consistent with crystal plasticity theory. [ABSTRACT FROM AUTHOR]