High temperature oxidation behavior and research status of modifications on improving high temperature oxidation resistance of titanium alloys and titanium aluminides: A review

Abstract:In this paper, the accurate description of the relationship between flow stress and strain of porous titanium alloys at various strain rates and temperatures were investigated with dynamic and quasistatic uniaxial compression tests for a further study on the processing mechanism of porous titanium material. Changes in their plastic flows were described through the one-dimensional Drucker-Prager (DP) constitutive model. Porous titanium alloys were micromilled in a DP simulation. After all parameters had been obtained in the DP model, the experimental and simulated true stress-strain curves and flow stress levels of two porous titanium alloys were compared to estimate the precision of the model. The findings were as follows. First, porous titanium alloys show deformation patterns characterized by pore collapse-induced deformation and have strong stress-hardening effects, but the patterns did not include noticeable plastic-flow plateaus. Second, porosity strongly affects the mechanical strength, strain-rate sensitivity, and temperature sensitivity of both alloys. Third, the DP model sufficiently describes the mechanical properties of both alloys at 25-300 • C and at strain rates of 1000-3000 s −1 , with a deviation of 10% or lower.

Section: Introductionmentioning

confidence: 99%

One-Dimensional Constitutive Model for Porous Titanium Alloy at Various Strain Rates and Temperatures

Liu

Wang

et al. 2017

“…Titanium alloys are widely used to produce different orthopedic devices and high-temperature structural components such as artificial hip joints and gas turbine components, respectively [1][2][3][4][5]. However, Co-Cr and Co-Cr-Mo alloys are also utilized as articular component in hip joints owing to their superior wear resistance than the conventional Ti alloys [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Previous works have reported on the present good biocompatibility and wear resistance of the Ti-Si alloys which are formed by the Ti and Ti 5 Si 3 phases [11,12] as well as the detrimental Ti 5 Si 3 formation in these alloys mainly due to its high crystallographic anisotropy [13]. Two-phase Ti+Ti 6 Si 2 B…”

Section: Introductionmentioning

confidence: 99%

Mechanical Alloying and Hot Pressing of Ti-Zr-Si-B Powder Mixtures

Bertoli

Ferreira

Freitas

et al. 2018

This work discusses microstructure evolution during ball milling and hot pressing of Ti-xZr-10Si-5B (x = 2 and 5 at. %) and Ti-xZr-20Si-10B (x = 5, 7, 10, 15 and 20 at. %) powder mixtures. Mechanical alloying was carried out in a ball mill using stainless steel balls and vials, 300 rpm and a ball-to-powder ratio of 10:1. Powders milled for 600 min were then hot-pressed (25 MPa) under vacuum at 1100 • C for 60 min. As-milled and hot-pressed samples were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and energy dispersive spectrometry (EDS). Peaks of Si and Zr disappeared in powders milled for 60 and 180 min, respectively, while the lattice parameters and cell volume of α-Ti were varied during ball milling up to 300 min indicating that supersaturated solid solutions were achieved. Ti 6 Si 2 B dissolving up to 10 at. % Zr was found in microstructure of hot-pressed Ti-xZr-10Si-5B (x = 2 and 5 at. %) and Ti-xZr-20Si-10B (x = 2, 5, 7 and 10 at. %) alloys. The amount of TiB and Ti 5 Si 3 was preferentially increased whereas the Ti 3 Si formed in microstructure of the hot-pressed Ti-15Zr-20Si-5B and Ti-20Zr-20Si-10B alloys.

“…The sharp friction between the tool and the workpiece causes the temperature to rise, while the poor thermal conductivity of the porous titanium makes the temperature unable to diverge well [9]. On the one hand, oxidation will appear if the temperature becomes too high, and oxide will stick to the tool, resulting in adhesive wear if the temperature reaches approximately 300 • C [10,11]. On the other hand, as the temperature Two titanium powders, made by Shijiazhuang Yida Co., Ltd., Shijiazhuang, China, 500# and 200#, with diameters less than 27 μm and 74 μm, respectively, are used.…”

Section: Introductionmentioning

confidence: 99%

Study on the Tribological Properties of Porous Titanium Sliding against Tungsten Carbide YG6

Liu

Wang

et al. 2017

Abstract:In the metal cutting process, the friction and wear behavior between the cutting tool and machined surface is the most important factor that affects the surface quality and the service life of the cutter. The irregular pore structure of porous titanium alloy has changed its mechanical properties and the processing technology. The friction and wear mechanism of the cutting tool and the machined surface is greatly different from the traditional dense metal processing because of the crumbling at the edges, tearing phenomenon and the pore agglomeration effect of chips. In this paper, the tribological characteristics and the wear mechanism of friction pair which was formed by porous titanium alloy material and hard alloy cutter were studied from cutting force, cutting speed and temperature in micro-cutting condition, and the influence of porosity on the wear rate and friction coefficient was analyzed. Results show that the main factor which influences the friction coefficient and wear rate is the porosity. The wear mechanisms of porous titanium materials were abrasive and oxidation wear while the wear mechanism of tungsten carbide YG6 was abrasive wear. The friction coefficient and wear rate of the relatively stable state are beneficial to improve the surface quality and tool life. As a result, in the micro-cutting process of porous titanium alloys, the best choice of machining parameters for different porosity materials are as follows: the load is about 8 N, the sliding speed is about 400 r/min and the temperature is about 300 • C.