Study of Metal, Silicon Carbide Crystals and Ceramic Bond Transfer to the Surface of Titanium Alloy during Grinding

2021 ◽  
Vol 316 ◽  
pp. 515-520
Author(s):  
Vladimir A. Nosenko ◽  
Alexander V. Fetisov ◽  
Nikita D. Serdyukov

The high adhesive activity of titanium alloys in interaction with abrasive materials is the main cause of poor grinding treatment. The most common abrasive material for grinding titanium alloys is silicon carbide. Silicon carbide wheels operate primarily in self-sharpening mode. Wear of the abrasive tool in the self-sharpening mode occurs as a result of brittle destruction of the fret. The purpose of the study was to determine experimentally the crystalline wear products of an abrasive tool, made of silicon carbide, on the treated surface during grinding of a titanium alloy. Samples of VT9 titanium alloy were processed by flat mortise grinding by a wheel of silicon carbide with the use of VOLTES coolant and the characteristic of the abrasive tool - 64CF80L7V. The treated surface was examined on the electron microscope Versa 3D Dual Beam. The condition of the treated surface testifies to the intensive adhesive interaction of the titanium alloy with the abrasive tool. The thickness of the metal deposits reaches 3 microns. As a result of morphological analysis, objects are identified on the treated surface, the appearance of which allows us to attribute them to crystals. The chemical composition of the selected objects was determined by a microprobe analysis in a microscope camera. On the basis of the conducted researches, a presence on the grinded surface of silicon carbide crystals of various sizes and a ceramic ligament is established.

2021 ◽  
Vol 316 ◽  
pp. 521-526
Author(s):  
Vladimir A. Nosenko ◽  
Alexander V. Fetisov ◽  
Semen P. Kuznetsov

The article summarizes the results of the of the titanium alloy surface morphology and chemical composition study after grinding with a wheel of cubic boron nitride on a ceramic bond. The titanium alloy was treated using the method of cut-in grinding in the finishing mode using a synthetic water-soluble lubricant-cooling liquid that does not contain mineral oil. The research was carried out using the FEI Versa 3D LoVac electron microscope. Digital photos of the titanium alloy surface at different magnifications are given. Individual objects’ morphology allows us to identify them as wear products of abrasive tools. The chemical composition of the selected objects was studied by local x-ray spectral analysis. CBN crystals are partially or completely pressed into the treated surface and covered with a layer of the treated material. On the surface of CBN crystals, there are chemical elements that are part of the abrasive tool bond.


Author(s):  
V. Nosenko ◽  
A. Fetisov ◽  
S. Kuznetsov

The results of the study of the morphology and chemical composition of the surface of 10895 electrical steel obtained during the first period of grinding with a wheel made of cubic boron nitride on a ceramic bond are presented. It is shown that in comparison with grinding in the same conditions of titanium alloy, the intensity of the adhesive interaction of the abrasive tool with the processed material is significantly less. Despite a significant decrease in the intensity of adhesive interaction with the abrasive material, wear products of the grinding wheel were found on the treated surface of the steel. The results of morphological and electron microprobe analyses allow to identify the products of wear, as the crystals of cubic boron nitride.


2021 ◽  
Vol 887 ◽  
pp. 287-293
Author(s):  
Vladimir A. Nosenko ◽  
S.V. Nosenko ◽  
V.E. Puzirkova

X-ray spectroscopic microanalysis was used to determine the concentration of titanium on the surface of the wear spot of a silicon carbide crystal during micro-scratching and the concentration of silicon on the treated surface after grinding by a wheel of silicon carbide. The wear resistance and grinding coefficient of titanium alloys under micro-scratching with single crystals and grinding with wheels made of corundum, silicon carbide, cubic boron nitride and diamond were determined. The morphology of the treated surface and the regularities of changes in the indicators of the grinding process of titanium alloys with circles of various characteristics were studied. The features of the process of grinding titanium alloys using various lubricants and coolants are shown. The influence of the characteristics of the abrasive tool and grinding modes on low-cycle fatigue on the operation of flat and round grinding of samples made of titanium alloys VT9 and VT22 was studied. The influence of abrasive material, grinding speed, feed and sparkout during finishing on low-cycle fatigue was analyzed. Based on the research, recommendations were given for choosing a rational characteristic of the abrasive tool and processing modes.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 266
Author(s):  
M.S.I. Chowdhury ◽  
B. Bose ◽  
S. Rawal ◽  
G.S. Fox-Rabinovich ◽  
S.C. Veldhuis

Tool wear phenomena during the machining of titanium alloys are very complex. Severe adhesive interaction at the tool chip interface, especially at low cutting speeds, leads to intensive Built Up Edge (BUE) formation. Additionally, a high cutting temperature causes rapid wear in the carbide inserts due to the low thermal conductivity of titanium alloys. The current research studies the effect of AlTiN and CrN PVD coatings deposited on cutting tools during the rough turning of a Ti6Al4V alloy with severe BUE formation. Tool wear characteristics were evaluated in detail using a Scanning Electron Microscope (SEM) and volumetric wear measurements. Chip morphology analysis was conducted to assess the in situ tribological performance of the coatings. A high temperature–heavy load tribometer that mimics machining conditions was used to analyze the frictional behavior of the coatings. The micromechanical properties of the coatings were also investigated to gain a better understanding of the coating performance. It was demonstrated that the CrN coating possess unique micromechanical properties and tribological adaptive characteristics that minimize BUE formation and significantly improve tool performance during the machining of the Ti6Al4V alloy.


2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.


2013 ◽  
Vol 554-557 ◽  
pp. 1961-1966 ◽  
Author(s):  
Yessine Ayed ◽  
Guenael Germain ◽  
Amine Ammar ◽  
Benoit Furet

Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.


2016 ◽  
Vol 704 ◽  
pp. 75-84 ◽  
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Pal Singh ◽  
Stella Raynova ◽  
Hui Yang Lu ◽  
...  

Blended Elemental Powder Metallurgy (BE-PM) is a very attractive method for producing titanium alloys, which can be near-net shape formed with compositional freedom. However, a minimization of oxygen pick-up during processing into manufactured parts is a big challenge for powder metallurgy of titanium alloys. In this paper, different approaches for preparing titanium alloy parts by powder compact extrusion with 0.05-0.1wt.% of oxygen pick-up during manufacturing are discussed. The starting materials were a powder mixture of HDH titanium powder, other elemental powders and a master alloy powder. Different titanium alloys and composites, such as Ti-6Al-4V, Ti-4Al-4Sn-4Mo-0.5Si, Ti-5Al-5V-5Mo-3Cr, and Ti-5Al-5V-5Mo-3Cr-5vol%TiB, with different profiles such as round and rectangular bars, a wedge profile, wire and tubes have been successfully manufactured on a laboratory and pilot-plant scale. Furthermore, a possible route for scaling up the titanium processing capabilities in the University of Waikato has also been discussed.


2021 ◽  
pp. 301-308
Author(s):  
V.V. Altukhova ◽  
R.F. Krupsky ◽  
A.A. Krivenok ◽  
O.G. Shakirova

It is shown that vibroabrasive treatment of hardened titanium alloy specimens contributes to an increase in their durability. This effect is explained by the removal of a defective surface layer containing microcracks and subject to the influence of residual tensile stresses. It is shown that the proposed stage of vibro-abrasive processing with ceramic granules makes it possible to almost completely remove iron introduced after vibro-impact surface hardening, which makes it possible to exclude the operation of etching in nitric acid from the technological process. The current state of research on durability in world science is briefly presented.


Author(s):  
Haiyang Fan ◽  
Yahui Liu ◽  
Shoufeng Yang

Ti–6Al–2Sn–4Zr–2Mo (Ti-6242), a near-[Formula: see text] titanium alloy explicitly designed for high-temperature applications, consists of a martensitic structure after selective laser melting (SLM). However, martensite is thermally unstable and thus adverse to the long-term service at high temperatures. Hence, understanding martensite decomposition is a high priority for seeking post-heat treatment for SLMed Ti-6242. Besides, compared to the room-temperature titanium alloys like Ti–6Al–4V, aging treatment is indispensable to high-temperature near-[Formula: see text] titanium alloys so that their microstructures and mechanical properties are pre-stabilized before working at elevated temperatures. Therefore, the aging response of the material is another concern of this study. To elaborate the two concerns, SLMed Ti-6242 was first isothermally annealed at 650[Formula: see text]C and then water-quenched to room temperature, followed by standard aging at 595[Formula: see text]C. The microstructure analysis revealed a temperature-dependent martensite decomposition, which proceeded sluggishly at [Formula: see text]C despite a long duration but rapidly transformed into lamellar [Formula: see text] above the martensite transition zone (770[Formula: see text]C). As heating to [Formula: see text]C), it produced a coarse microstructure containing new martensites formed in water quenching. The subsequent mechanical testing indicated that SLM-built Ti-6242 is excellent in terms of both room- and high-temperature tensile properties, with around 1400 MPa (UTS)[Formula: see text]5% elongation and 1150 MPa (UTS)[Formula: see text]10% elongation, respectively. However, the combination of water quenching and aging embrittled the as-built material severely.


2010 ◽  
Vol 150-151 ◽  
pp. 51-55 ◽  
Author(s):  
Jun Du ◽  
Ping Zhang ◽  
Jun Jun Zhao ◽  
Zhi Hai Cai

Titanium alloys are susceptible to sand erosion, hard zirconium nitride coatings have been deposited onto titanium alloys by Physical vapor deposition (PVD) in order to improve erosion resistance. Al and Cu were added into ZrN coatings to strength and toughing the coating. The microstructure and mechanical properties of ZrAlCuN coating were studied. Erosion tests were conducted to evaluate anti-erosion ability. Erosion rates were measured and characteristic damage features were identified on the surface of eroded specimens. The mechanisms of erosion are discussed in order to explain the promising performance of materials in erosive conditions. It was found that there is an significant increase of erosion resistance because of the increase of hardness and toughness.


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