Fatigue behavior of Ti-6Al-4V alloy modified by plasma immersion ion implantation: temperature effect

Author(s)

Velloso, Veronica ; Nozaki, Leonardo ; Tapia, Diego ; Cioffi, Maria Odila ; Oliveira, Rogerio ; Barboza, Miguel ; Voorwald, Herman ; Henaff, G

• Document type: Journal article
• Source: CSNDD 2012 - INTERNATIONAL CONFERENCE ON STRUCTURAL NONLINEAR DYNAMICS AND DIAGNOSIS; v. 165, p. 6-pg., 2018-01-01.

Abstract

This research studied Ti-6Al-4V alloy behavior with two (2) different microstructure subjected to nitrogen addition by PIII treatment, with and without sample heating, under cyclic load. PIII conditions, at 390 degrees C, were DC voltage of 9.5 kV, frequency of 1.5 kHz and pulse of 40 mu s. PIII conditions, with sample heating at 800 degrees C, were 7 kV, 0.4 kHz and 30 mu s. Axial fatigue tests were performed on untreated and treated samples for resistance to fatigue comparison. The untreated Ti-6Al-4V had an annealed microstructure, PIII treatment at 390 degrees C resulted in a microstructure that has no nitride layer or diffusion zone. In the PIII treatment at 800 degrees C, the microstructure presented nitride layer and diffusion zone. Resistance to fatigue decreased with PIII treatments in both temperatures. At 390 degrees C, the treatment created deformation regions and cracks on surface due to nitrogen implantation that formed solid solution with titanium and imposed lattice strains on the crystal lattice. At 800 degrees C, bulk ductility decrease, increasing of alpha Ti proportion in microstructure due to a case formation and the presence of a ceramic layer dropped fatigue resistance of Ti-6A-4V alloy. (AU)

• FAPESP's process: 15/00331-2 - Ti-6Al-4V alloy fatigue phenomenon study modified by plasma immersion ion implantation treatment (PIII)
• Grantee: Verônica Mara de Oliveira Velloso
• Support Opportunities: Scholarships in Brazil - Post-Doctoral