Search Results

This work intends to analyze the influence of the stress and temperatures used in creep mechanical tests in the types of fractures that occurred in the superalloy Inconel 718. For this, the superalloy was subjected to creep tests under the conditions 625 to 814 MPa at temperatures of 650, 675 and 700°C. After the tests, the fractured samples were cleaned on an ultrasound and subjected to microstructural analysis using the technique of scanning electron microscopy. Images were performed with different increases in order to analyze the type of fracture that occurred in the material. The elongated sample and its reduction in area were also measured in order to study the effects of different conditions used in the creep tests under material's fracture.

The present study concerns laser surface nitriding of Ti-6Al-4V. The Ti-6Al-4V alloy was submitted a superficial treatment of pulsed laser Nd:YAG (λ=1.064 μ\m) in atmosphere of 40wt% nitrogen-60wt% argon. The samples were characterized by optical microscopy and electron scanning microscopy. The microstructure of the surface nitrided Ti-6Al-4V consists of TiN dendrites distributed in α--Ti matrix. It can be noted that there is a significant enhancement in surface roughness after surface nitriding (6.60 μm) as compared to the as received Ti-6Al-4V (0.46 μm). The microhardness of the surface is improved to 1100 VHN as compared to the 340 VHN of substrate.