The effects of Nb and Mo addition, with different contents, on the microstructure and some mechanical properties of Ti-6Al-4V alloy were investigated. Treatments were performed at various high temperatures about 1200 and 1300 °C for 3h using vacuum furnace as first treatment and using an argon atmosphere as second treatment. The samples were characterized by X-ray diffraction and the influence of processing temperature on microstructure was studied, the microstructural evolution was evaluated by optical microscopy and SEM. The results revealed that the Nb and Mo elements added to the titanium alloy stabilized the β phase and changed the lattice parameters of α phase. Microstructural observations, phase analysis shown that Ti-6Al-4V alloy contain single phase and increasing Nb and Mo contents the equiaxed grain is refined, and reduction in the prior β grain size. Moreover, Nb/Mo addition up to 10 wt.% increases the volume fraction of β phase in the microstructure. Some mechanical properties such as hardness, Young's modulus and fracture toughness were achieved and tensile test was performed at room temperature. Experimental results revealed good mechanical properties including a low Young's modulus and high deformability, the hardness values of the alloy is about 350-570 HV and the fracture toughness values K_IC are ranging from 16.8 MPa m^1/2 to 28.5 MPa m^1/2 depending on Nb/Mo contents.

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The purpose of this paper is to present a new giant magnetoresistance (GMR) sensor, in eddy current testing technique for surface defect detection, in conducting materials, we show that the GMR based eddy currents probe is more sensitive than the inductive probe. A flat coil mounted on ferrite pot used to produce an alternate magnetic field, which gives rise to eddy currents in the material under test. Aluminum plates use with defects have nominal depths, widths, and lengths. The defects scanned with the sensing axis perpendicular to the defect length. Two parameters extracted from the GMR output voltage signal obtained, and a simple correlation between the defect’s dimensions and the GMR output voltage proposed.