Dry sliding wear mechanisms of the Ti6Al4V alloy

Dry sliding wear of Ti–6Al–4V alloy as influenced by the counterface and sliding conditions

Wear and corrosion behaviour of Ti–13Nb–13Zr and Ti–6Al–4V alloys in simulated physiological solution

Friction and wear of titanium alloys sliding against metal, polymer, and ceramic counterfaces

The objective of the research was to improve the wear resistance of titanium alloys by ball burnishing process. Burnishing process parameters such as burnishing speed, burnishing feed, burnishing force and number of pass were considered to minimize the specific wear rate and coefficient of friction. Taguchi optimization results revealed that burnishing force and number of pass were the significant parameters for minimizing the specific wear rate, whereas the burnishing feed and speed play important roles in minimizing the coefficient of friction. After burnishing surface microhardness increased from 340 to 405 Hv, surface roughness decreased from 0.45 to 0.12 μm and compressive residual stress were generated immediately below the burnished surface. The optimization results showed that specific wear rate decreased by 52%, whereas coefficient of friction was reduced by 64% as compared to the turned surface. The results confirm that, an improvement in the wear resistance of Ti–6Al–4V alloy has been achieved by the process of ball burnishing.

Wear resistance enhancement of titanium alloy (Ti–6Al–4V) by ball burnishing process

Effects of load and sliding speed on the tribological behaviour of Ti6Al4V plasma nitrided different temperatures

The chemical and physical characteristics of ion-nitrided surface layers, obtained on α-β titanium alloys, are examined and correlated both with the working conditions adopted in the ion-nitriding process and with the alloy chemical composition. Besides the influence of the working parameters on the morphology and on the microstructures of the ion-nitrided surface layers, mainly the alloy element distributions both in surface coatings and in the substrate are analysed for five α-β titanium alloys of industrial use, and for titanium c,p. as reference, ionnitrided at various treatment temperatures. The nitriding process forms, on titanium alloy parts, high-hardness surface layers consisting of TiN (δ phase) and Ti2N (ɛ phase) nitrides and an interstitial solid solution of nitrogen in the close-packed hexagonal lattice of titanium (α phase). The presence and the extent of these phases as well as the ion-nitrided layer morphology are essentially determined by the alloy chemical composition and the working parameters. In particular a low-temperature treatment produces an extended nitrogen diffusion in the matrix beneath a thin continuous nitrided layer, while a high-temperature treatment produces prevalently a continuous nitrided surface layer. The alloy element distribution appears differentiated in the various phases and may be correlated with the different affinity of these elements with nitrogen.

Surface engineering and chemical characterization in ion nitrided titanium and titanium alloys

Surface engineering and chemical characterization in ion-nitrided titanium and titanium alloys

Surface layers having elevated hardness were produced by ion nitriding of titanium and α-β alloys of Ti-6wt.%Al-4wt.%V, Ti-4wt.%Al-2wt.%Sn4wt.%Mo and Ti-4wt.%Al-2wt.%Mn. The treatment was conducted at temperatures between 1073 and 1273 K for times of 4–32 h, using gaseous mixtures of nitrogen and hydrogen containing 20–80 vol.% nitrogen. X-ray diffraction, optical microscopy and microhardness were used to characterize the hardened surfaces. In most of the samples, this surface was composed of the phases δ (TiN type), ϵ (Ti 2 N type) and α (solid solution of nitrogen in titanium); in other cases only the δ and α phases were present. The operating parameters which influence the composition of the layer were identified and the particular crystalline texture of the ϵ phase is discussed.

B. Tesi

Papers

Dry sliding wear mechanisms of the Ti6Al4V alloy

Effects of load and sliding speed on the tribological behaviour of Ti6Al4V plasma nitrided different temperatures

Surface engineering and chemical characterization in ion nitrided titanium and titanium alloys

Surface engineering and chemical characterization in ion-nitrided titanium and titanium alloys

Characterization of surface layers in ion-nitrided titanium and titanium alloys