Microstructure Of Pure Titanium Research Articles

Effect of chemical-heat treatment on the properties of titanium

The aim of this study is to evaluate the properties and microstructure of pure titanium after its chemical heat treatment (CHT) by boriding and nitriding. Nitriding and boriding were both done in powder backfill for ten hours. The temperature of the nitriding was 550 °C. The temperature of the boriding was 1000 °C. Both processes led to the creation of a thin surface layer of nitrides and borides which affected wear resistance and also they affected corrosion resistance of the surface of the analyzed samples.

Characterization of Ti–6Al–(4V–7Nb–4Mo) Biomedical Alloys Produced by Powder Metallurgy Method

Pure titanium and titanium-based alloys are the most widely used metallic biomaterials in biomedical applications. At that, the Ti–6Al–4V alloy is considered as the most commonly exploited alloy among all alloys that contain titanium. However, it is known that the vanadium metal that constitute this alloy has a potential toxic effect. In this study, the powder metallurgy (PM) method was used for the production of pure-Ti, as well as Ti–6Al–4V, Ti–6Al–7Nb, and Ti–6Al–4Mo alloys. Niobium and molybdenum elements, one of the alloying metals, have been proposed as a substitution of vanadium due to its possible toxic effects. Produced samples were characterized by SEM, EDX, XRD, as well as microhardness, density, and Tafel extrapolation method. The analysis results showed that microstructure of pure titanium and titanium-based alloys differ. Besides, the XRD analysis showed that the phases of doped metals (Nb, V, and Mo) were found as Al0.23Nb0.07Ti0.70, Ti0.80V0.20, and AlMoTi3. Microhardness and Tafel extrapolation values were quite remarkable by comparing them to each other. The main important result of the research was obtained pure titanium and titanium alloys with homogeneous microstructure produced by the powder metallurgy method.

Investigation of Temperature Effects on Microstructure of Pure Titanium

Investigation of Temperature Effects on Microstructure of Pure Titanium

Fabrication of the Ti5Si3/Ti composite inoculants and its refining mechanism on pure titanium

The in situ Ti5Si3/Ti inoculants were successfully prepared by vacuum arc-melting and melt-spinning method. An efficient route by adding a small quantity of Ti5Si3/Ti inoculants to Ti melt has been first proposed to modify the coarse grains of as cast microstructure of pure titanium in this paper. It was found that the microstructure of ribbon inoculants was cellular structure that composed of Ti5Si3 and α-Ti phases. The grain refining effect of the inoculants was significantly improved with the adding ratio range from 0.2% to 0.5% in weight. With the increase of addition amount of inoculants on Ti melt, the tensile strength, yield strength and microhardness of pure titanium are significantly improved except elongation. The excellent grain refining effect can be attributed to the heterogeneous nucleation of the titanium grain on the precipitated Ti5Si3 phases in the Si-rich regions and the constitutional supercooling of Si in the Si-poverty regions. It is suggested that the in situ Ti5Si3/Ti inoculants is a promising inoculants for titanium alloys.

In-situ observation of dislocation and analysis of residual stresses by FEM/DDM modeling in water cavitation peening of pure titanium

In this paper, in order to approach this problem, specimens of pure titanium were treated with WCP, and the subsequent changes in microstructure, residual stress, and surface morphologies were investigated as a function of WCP duration. The influence of water cavitation peening (WCP) treatment on the microstructure of pure titanium was investigated. A novel combined finite element and dislocation density method (FEM/DDM), proposed for predicting macro and micro residual stresses induced on the material subsurface treated with water cavitation peening, is also presented. A bilinear elastic-plastic finite element method was conducted to predict macro-residual stresses and a dislocation density method was conducted to predict micro-residual stresses. These approaches made possible the prediction of the magnitude and depth of residual stress fields in pure titanium. The effect of applied impact pressures on the residual stresses was also presented. The results of the FEM/DDM modeling were in good agreement with those of the experimental measurements.

Investigation of Mechanical Properties of Nanostructured Titanium Processed by Warm ECAP Followed Cold Rolling

In this work, ECAP technique was combined with cold rolling process in order to enhance mechanical properties and microstructure of pure Titanium. Coarse grain (CG) Titanium with original grain size of 150 μm had been pressed by ECAP at 425oC by 4, 8 and 12 passes, respectively. This process then was followed by rolling at room temperature with 35%, 55%, and 75% rolling strains. After two steps, mechanical properties such as strength, hardness and microstructure of processed Titanium have been measured. The result indicated significant effect of cold rolling on tensile strength, hardness and microstructure of ECAP-Titanium.

Influence of hydrogen on hot deformation behavior and microstructure of pure titanium

The influence of hydrogen on the hot deformation behavior and the microstructure after deformation of pure titanium crystal was investigated. The results show that hydrogen in pure titanium crystal can reduce the flow stress of hot deformation; The flow stress peak is decreased best by 60% in a Ti-H crystal specimen deformed at 600–800°C and the peak flow stresses exhibit a trough behavior with the hydrogen concentration, that is, there is a minimum of peak flow stress at a certain hydrogen concentration. Through the analysis of microstructure, the great amounts of needle-like martensite and the small number of dislocations within the sub-grains in Ti-H crystal after hot deformation. These indicate that the hydrogen can increase the volume of β phase and can promote the dynamic recovery in the deformation process at high temperature, as a result, it decreases the flow stresses effectively.

Investigation of water cavitation peening-induced microstructures in the near-surface layer of pure titanium

The influence of water cavitation peening (WCP) treatment on the microstructure of pure titanium was investigated. The microstructural evolution in the near-surface of pure titanium as a function of WCP time was characterized by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). After WCP treatment, changes in the microstructure, as well as residual stress and surface morphologies as functions of WCP time, were recorded using a novel experimental design involving an in situ observation function. The obtained results indicate that twinning plays an important role in the plastic deformation and residual stresses of hexagonal close-packed (HCP) structured metal materials, and therein, that the deformation twinning and twinning interaction were induced by WCP in the strengthening layer. A stable compressive residual stress layer was found in the near-surface of the investigated pure titanium.