Surface Layer Of Titanium Alloy Research Articles

Peculiarities of High-Energy Thermal Effect on Structure and Properties of Surface Layers of Titanium Alloys During Plasma Cutting

Peculiarities of High-Energy Thermal Effect on Structure and Properties of Surface Layers of Titanium Alloys During Plasma Cutting

Influence of Preliminary Ultrasonic Treatment on the Structure of Implanted Surface Layers of Titanium Alloy

Influence of Preliminary Ultrasonic Treatment on the Structure of Implanted Surface Layers of Titanium Alloy

Effect of cutting process adjustment on crystallographic texture of machined surface layer of titanium alloy

Effect of cutting process adjustment on crystallographic texture of machined surface layer of titanium alloy

STRUCTURE OF COMMERCIAL TITANIUM SUBJECTED TO LOW-TEMPERATURE ION NITRIDING

The structural-phase state of commercial titanium of grades ВТ1-00 (VT1-00) and ВТ1-0 (VT1-0) has been studied in the initial state and after various types of low-temperature ion nitriding. In the initial state, the VT1-00 and VT1-0 alloys have a single-phase α-Ti structure with a hexagonal close-packed crystal lattice. The hardness of titanium is 140–150 HV 10. It has been shown that ion-beam nitriding of VT1-00 alloy at low temperatures of 350 and 450 °С leads to the formation of thin (up to 5 μm) nitrogen-hardened layers with a hardness of 160–180 HV 0.05. As a result of ion implantation at temperatures of 500 and 550 °C, a nitrogen-modified layer with a microhardness of 190–220 HV 0.05 is formed in the surface layers of the VT1-00 titanium alloy, containing a solid solution of nitrogen in the α-Ti matrix phase. Nitrogen implantation of the VT1-00 alloy at a temperature of 620 °C leads to the formation of titanium nitrides TiN0.26, ε-Ti2N, η-Ti3N2-x in the surface layer of titanium alloy. The microhardness of VT1-00 titanium treated with nitrogen ions at 620 °C increases to 360 HV 0.05. In the case of ion-plasma nitriding (IPN) of VT1-0 titanium at 550 °C for 5 h, a nitrogen-modified layer up to 20 μm deep is recorded in its surface layer, containing isomorphic phases: α-Ti and titanium nitride TiN0.26. The microhardness of the VT1-0 titanium alloy subjected to IPN is 190 HV 0.01.

Composition of Surface Layers of Titanium Alloy after Electrospark Alloying

The effect of the regime of electrospark alloying (ESA) on the thickness, hardness, and phase composition of the alloyed hardened layer on the surface of specimens of titanium alloy VT1-0 is studied. The thickness of the layer depends considerably on the parameters of the ESA process, and the hardness level is determined by the phase composition.

Hardening and welding with a fiber laser as the methods of purposeful formation of the structure and properties of VT6 titanium alloy

The results of studying microstructure and hardness of surface layers of nickel alloy welded on titanium α + β alloy using fiber laser after their combined hardening under the effect of laser radiation are presented. Laser cladding makes it possible to form coatings with high hardness and quenching structures in surface layers of titanium alloy. Hardness of welded metal after the high-speed cooling from the melt temperature on the titanium substrate surface is larger than the density of martensite alloy formed in the titanium alloy after quenching.

Experimental Investigation on Grinding Temperature of Titanium Alloy

Titanium alloy has been widely used in aeronautics and astronautics industry owing to its unique combinations of properties. The unique physical and chemical properties of titanium alloy make it a typical difficult-to-machine material. The elevated temperatures at the machining zones may cause thermal damage, residual stress and micro-structural changes in the surface layer of titanium alloy during grinding. In this study, grinding experiments were performed on the titanium alloy, and the grinding temperature was experimentally tested with the grindable thermocouples. The effects of the grinding parameters on the grinding temperature were analyzed. The grinding temperature rises with the increase of grinding speed and grinding depth.

Physical Base of the Metallic Gradient Surface Layers of Titanium Alloys Formed under Ion Implantation

The results of microstructure and phase composition investigations of titanium in different structural states (with average grain sizes of 0.3 μm, 1.5 μm, 17 μm, 38 μm) implanted by Al ions using the «Raduga-5» and MEVVA–V.RU sources are presented. The size, shape and localization of the formed phases (TiO2, Ti2O, TiC, Ti3Al, TiAl, Al3Ti) depend strongly on the grain size of titanium target. In polycrystalline titanium after implantation by Al-ions the secondary phases (Ti3Al, TiAl, TiO2, TiC) formed in the body of grains of titanium matrix. It is shown that the nanostructural particles of TiO2 phase are located mainly on dislocations in the body of target grains. An ordered Ti3Al phase is located at a depth of more than 200 nm in the implanted layer along the boundaries of the titanium grains. The TiAl3 phase formed on the grain boards in subnano- and microstructural state of titanium targets. The improvement of the mechanical properties of titanium due to formation of the gradient structure of ion-alloyed surface layer was obtained.

Electron-beam surface treatment of alloys based on titanium, modified by plasma from an electrical explosion of conducting material

We present the results from investigating the phase composition, structure, and properties of surface layers of titanium alloys subjected to combined treatment that includes plasma alloying the electric explosion of a carbon fiber with a quantity of TiB2 powder and subsequent irradiation with a high-intensity electron beam. The formation of a multilayer, multiphase structure in the submicro- and nano-sized ranges is observed. It is shown that the properties of a alloyed layer exceed those of a bulk sample many times over.

Effect of temperature and degree of rarefaction of the oxygen-bearing medium on the process of oxynitriding of titanium alloys

Dependence of the physicochemical characteristics of surface layers of titanium alloys on the mode of oxynitriding, i.e., the temperature of saturation in the nitrogen-bearing medium and the degree of rarefaction of the oxygen-bearing medium in the process of oxygen modifying of the formed nitride layer, is studied. The conditions ensuring formation of a homogeneous oxynitride layer on the surface are determined.

Effect of Periodic High-Voltage Discharge in a Flow of Liquid on the Surface Layers of Structural Steels and Titanium Alloys

Results of a study of the effect of electric pulse treatment with the use of high-voltage periodic discharge in a flow of water on the structure and hardness of surface layers of specimens of steels 45KhN2MFA, 30Kh3NMAF, 12Kh18N10T and titanium alloys OT4-1 and VT6 are described. It is shown that the structure and properties of the surface in the zone of the action of electric discharge change due to the rapid fusion, crystallization, and rapid hardening of microvolumes of specimens subjected to the highly concentrated energy action. The microhardness of the surface of specimens of pearlitic steels after such a treatment is higher than after volume quenching. The microhardness of the surface layers of specimens of austenitic steel 12Kh18N10T decreases. Hardening of the surface layers of titanium alloys under the action of high-voltage discharge is substantially higher than in the case of quenching, which seems to be connected with their saturation with oxygen and nitrogen from the ionized ambient. Some regular features of the influence of the conditions of periodic discharge on the structure and properties of surface layers of the studied materials are described.

Adhesion wear mechanisms under dry friction of titanium alloys in vacuum

Physicochemical processes taking place in the surface layers of titanium alloys were studied. For vacuum conditions, a range of external parameters was proved to exist where the alloys have high wear resistance and a low coefficient of friction. The transition from seizure, with tearing of the material at a large depth, to fatigue wear is related to surface hardening due to α / ag β transitions under friction. Thermodynamic parameters were calculated and the criteria of protective secondary structure formation defined.

Ion-beam modification of the surface layers of titanium alloys

Ion-beam modification of the surface layers of titanium alloys

Kinetics of the processes of gas impregnation and sublimation of titanium alloys in vacuum at temperatures of 1123 and 1273�K

This paper studies the kinetics of the processes of interaction of titanium alloys with the residual gases of a vacuum and reveals their influence on the structure of the surface layers of titanium alloys. Aluminum, cannot sublimate since it possesses the greatest affinity for oxygen among the alloy elements, and titanium and zirconium, judging from the pressure of the staturated vapors of the pure metals and their oxides, cannot sublimate because of the low values of the parameters. An increase in temperature to 1273 degrees K does not qualitatively change the character of interaction of PT-7M, PT3V, VT6S, and OT4-1 alloys with the residual gases of the vacuum, but intensifies these processes. In VT5-1, a qualitative change in the processes as the result of activation of sublimation of tin from the alloy is observed.