Characterization of Titanium-Based Films Deposited by DC Sputtering Reactive on AISI 1018 Steel

The coated surfaces first layer Ti and second layer TiO2 as coating Nanostructured thin films of using DC sputtering on structural steel (AISI l018) and study characterization of coating SEM/EDS inspection shown a clearly perfect incorporation of layer by dc sputtering a granular structure of the layer with a variable hemisphere’s forms varied from 33 to 46 nm in size. X-XRD test complete for specimen indicates was found anatase phase titanium dioxide, the resulted coating layer of the target of Ti powders gives different morphology from the Ti layer alone The Specimens roughness average of coated Ti and TiO2with respectively was 4.831nm, 7.93 nm. Found that titanium layer will show a major part in increasing the bonding with improving the bond between the substrate steel AISI (1018) and the titanium oxide layer. The Vickers hardness increases when the coating with a layer of titanium with an oxygen content of ceramic layer is formed from 192.3 HV to 227 for Ti as well as important increase was detected in the Tio2 coating to 240 HV. In addition, Ti and Tio2 thin layer considered as a good barrier for hydrogen permeation through steel structure especially at cathode protection in pipelines.

Analyzing metallurgical interaction during arc surfacing of barrier layers on titanium to prevent the formation of intermetallics in titanium-steel compounds

This paper considers a possibility to obtain high-quality butt junctions of bimetallic sheets from steel clad with a layer of titanium, with the use of barrier layers. The task that was tackled related to preventing the formation of Ti-Fe intermetallic phases (IMPs) between the steel and titanium layer. The barrier layers (height ~0.5 mm) of vanadium and copper alloys were surfaced by arc techniques while minimizing the level of thermal influence on the base metal. To this end, plasma surfacing with a current-driving wire and pulsed MAG surfacing were used. The obtained samples were examined by methods of metallography, X-ray spectral microanalysis, durometric analysis. It has been established that when a layer of vanadium is plated on the surface of titanium, a defect-free structure of variable composition (53.87–65.67) wt % Ti with (33.93–45.54) wt % V is formed without IMPs. The subsequent surfacing of steel on a layer of vanadium leads to the formation of eutectics (hardness up to 5,523 MPa) in the fusion zone, as well as to the evolution of cracks. To prevent the formation of IMPs, a layer of bronze CuBe2 was deposited on the surface of vanadium. The formed layer contributed to the formation of a grid of hot cracks. In the titanium-vanadium-copper transition zones (0.1–0.2 mm wide), a fragile phase was observed. To eliminate this drawback, the bronze CuBe2 was replaced with bronze CuSi3Mn1; a defect-free junction was obtained. When using a barrier layer with CuSi3Mn1, a defect-free junction was obtained (10–30 % Ti; 18–50 % Fe; 5–25 % Cu). The study reported here makes it possible to recommend CuSi3Mn1 as a barrier layer for welding bimetallic sheets "steel-titanium". One of the applications of the research results could be welding of longitudinally welded pipes of main oil and gas pipelines formed from bimetallic sheets of steel clad with titanium.

An Anodized Titanium/Sol-Gel Composite Coating with Self-Healable Superhydrophobic and Oleophobic Property

Superhydrophobic and oleophobic surfaces have attracted increasing attention because of their self-cleaning properties. A composite coating composed of anodized titanium and sol-gel (TiAO/SG) was developed and has good superhydrophobic and oleophobic property. The anodized titanium coating was prepared on the titanium substrate and then a sol-gel layer was coated on the surface of the anodized titanium layer to obtain a composite coating with superhydrophobic and oleophobic properties. The adhesion weight of glycerol on the surface of the superhydrophobic titanium wire decreased to 4.8% of that of untreated titanium wire, which showed that the material had good oleophobic property. This new composite coating could achieve self-healing superhydrophobicity by releasing loaded perfluorodenytriethoxysilane to the surface of the coating. Given its superhydrophobicity, self-healing and wear resistance, the TiAO/SG coating was expected to achieve healable self-cleaning protection in titanium devices.

Observation of Cells on a Simulated Titanium Surface with Transparency

The main driving force of osseointegration on titanium implants is believed to be the calcification caused by cellular activity. However, owing to the opacity of bulk titanium, live cells on titanium surfaces cannot be observed using an inverted microscope. To overcome this limitation, this study proposes a transparent titanium thin layer as a simulated titanium surface that allows live-cell observation from below. The titanium layer was fabricated on a polystyrene culture dish by magnetron DC sputtering using a pure Ti(JIS1) target. The titanium layer was characterized by transparency, composition, structure, and wettability. Osteoblast-like cells were cultured in the titanium-coated dishes. The cell culture was observed periodically using an inverted microscope, and the images were compiled into time-lapse videos. Cells on the titanium layer were characterized by movement speeds and doubling times. The titanium-coated dish was transparent gray, and its transmittance profile was consistent with that of the polystyrene dish. The titanium layer showed similarities to bulk titanium surfaces in terms of composition and structure; that is, it showed an oxidized titanium outermost layer and titanium metal basal layer. The wettability of the titanium layer was hydrophilic with mean contact angles of 67.52°. Osteoblast-like cells successfully adhered to the titanium layer and proliferated to confluence. The time-lapse videos demonstrated active movement of the cells on the titanium layer, which suggested the involvement of the titanium surface in cellular motility. The cell culture on the titanium layer can be considered cell culture on a titanium surface. In short, the titanium layer enabled the acquisition of information for living cells on titanium that has either been unknown or analogically understood based on cell culture on polystyrene dishes.

The impact of tool point angle and interlayer gap width on interface borehole quality in drilling CFRP/titanium stacks

Although substantial research work has been conducted in order to understand and improve the drilling of multi-material aerospace stacks, some key aspects related to process and tool parameters and their impact on the interface quality still need to be addressed. This paper reports on the research conducted to investigate the impact of tool point angle and interlayer gap width on borehole quality, focussing on the interface region. A number of drilling tests were carried out using tools with different point angles and CFRP/titanium stacks with different interlayer gap widths. The results show that the damage on the CFRP interlayer surface is caused by the drilling of the titanium layer, as some of the upwards-travelling titanium chips penetrate into the stack interface. An increase in tool point angle results in larger entry burrs on the titanium interlayer surface, which is attributed to the correlation between tool point angle and thrust force and the capability of tools with low point angles to remove damage generated by surface skidding. The introduction of an interlayer gap promotes the ingress of titanium chips into the stack interface, thereby leading to more pronounced interface damage.

The Interface and Fabrication Process of Diamond/Cu Composites with Nanocoated Diamond for Heat Sink Applications

The coefficients of thermal expansion (CTE) and thermal conductivity (TC) are important for heat sink applications, as they can minimize stress between heat sink substrates and chips and prevent failure from thermal accumulation in electronics. We investigated the interface behavior and manufacturing of diamond/Cu composites and found that they have much lower TCs than copper due to their low densities. Most defects, such as cavities, form around diamond particles, substantially decreasing the high TC of diamond reinforcements. However, the measurement results for the Cu-coated diamond/Cu composites are unsatisfactory because the nanosized copper layer on the diamond surface grew and spheroidized at elevated sintering temperatures. Realizing ideal interfacial bonding between a copper matrix and diamond particles is difficult. The TC of the 40 vol.% Ti-coated diamond/Cu composite is 475.01 W m−1 K−1, much higher than that of diamond/Cu and Cu-coated diamond/Cu composites under equivalent manufacturing conditions. The minimally grown titanium layer retained its nanosized and was consistent with the sintering temperature. Depositing a nanosized titanium layer on a diamond surface will strengthen interfacial bonding through interface reactions among the copper matrix, nanosized titanium layer and diamond particles, reducing the interfacial thermal resistance and exploiting the high TC of diamond particles, even if defects from powder metallurgy remain. These results provide an important experimental and theoretical basis for manufacturing diamond/Cu composites for heat sink applications.

Research of stress distribution in the cross-section of a bimetallic perforated plate perpendicularly loaded with concentrated force

The paper presents the stress distribution along the plate thickness in a bimetallic steel – titanium circular, axially symmetrical perforated plate produced in the technological process of explosion welding. The steel layer is the layer that transfers the load in the plate, while the titanium layer is used to improve the properties of the plate, e.g. corrosion resistance, thermal transmittance, etc. in the plate. Two cases of fastening were considered, i.e. a freely supported and fixed plate. Such plates are used in various engineering structures, e.g. simply supported plates can be used in loose material screens, while plates are fixed in heat exchangers. The load was assumed as a concentrated force applied perpendicularly to the plate surface. The results obtained numerically using the finite element method were compared with the results calculated according to the analytical equations. It has been shown that the difference in the results of equivalent von Mises stress calculations does not exceed 13%. The research results presented in the paper can be used by engineers to design bimetallic perforated plates perpendicularly loaded to their surface.