Nickel Alloy Matrix Research Articles

High-Temperature Friction and Wear Behavior of Nickel-Alloy Matrix Composites with the Addition of Molybdate

To improve the tribological characteristics of materials employed in spatial mechanisms, there is a significant requirement to develop solid lubricating composites with superior performance. This study investigates the tribological characteristics of composites consisting of a nickel matrix combined with silver molybdate and barium molybdate. The experimental analysis focuses on evaluating the tribological behaviors of these composites from 25 °C to 800 °C. The findings indicate that the combined application of silver molybdate and barium molybdate resulted in enhanced self-lubricating properties of the composites, particularly at temperatures over 400 °C. The inclusion of both silver molybdate and barium molybdate in the composite resulted in the achievement of a low friction coefficient (0.34–0.5), as well as a wear rate ranging from 0.47 to 1.25 × 10−4 mm3 N−1m−1, within the temperature range of 400 to 800 °C. Furthermore, an analysis was conducted to examine the wear processes of the composites at various sliding temperatures. This analysis was based on the evaluation of the chemical composition and morphologies of the sliding surfaces, which were verified by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy.

Modelling and Deliberation of Multireinforcement Surface on Tribothermal Adsorption Performance of Nickel Alloy Matrix Hybrid Nanocomposite

The present research work is aimed at developing a nickel alloy (Ni-Cr) matrix hybrid nanocomposite comprising 5 wt%, 10 wt%, and 15 wt% of alumina nanoparticles (Al2O3) size of 50 nm with stable weight percentage (5 wt%) of titanium dioxide (TiO2) nanoparticle via vacuum die casting process for an automobile brake pad application. The deliberation of multireinforcement surface on nickel alloy matrix tribological performance was evaluated by constant sliding distance (200 m) on dry sliding condition via rotating pin on disc apparatus with different loading conditions of 10 N, 30 N, 50 N, and 70 N under the sliding velocity of 0.25 m/sec, 0.5 m/sec, and 0.75 m/sec, respectively. The influences of alumina and titanium dioxide nanoparticles in the nickel alloy matrix resulted in the thermal conductivity increasing by 18% compared to unreinforced nickel alloy. After temperature drop, the coefficient of thermal expansion for nickel alloy hybrid composite decreases progressively with increased reinforcement content as 10 wt% Al2O3/5 wt% TiO2. Further inclusion of both Al2O3 and TiO2 in nickel alloy was increased nominally. The thermal adsorption characteristic on composites mass loss was decreased while temperature increased from 28°C to 1000°C.

Matrix Composite Coatings Deposited on AISI 4715 Steel by Powder Plasma-Transferred Arc Welding. Part 3. Comparison of the Brittle Fracture Resistance of Wear-Resistant Composite Layers Surfaced Using the PPTAW Method.

This article is the last of a series of publications included in the MDPI special edition entitled “Innovative Technologies and Materials for the Production of Mechanical, Thermal and Corrosion Wear-Resistant Surface Layers and Coatings”. Powder plasma-transferred arc welding (PPTAW) was used to surface metal matrix composite (MMC) layers using a mixture of cobalt (Co3) and nickel (Ni3) alloy powders. These powders contained different proportions and types of hard reinforcing phases in the form of ceramic carbides (TiC and WC-W2C), titanium diboride (TiB2), and of tungsten-coated synthetic polycrystalline diamond (PD-W). The resistance of the composite layers to cracking under the influence of dynamic loading was determined using Charpy hammer impact tests. The results showed that the various interactions between the ceramic particles and the metal matrix significantly affected the formation process and porosity of the composite surfacing welds on the AISI 4715 low-alloy structural steel substrate. They also affected the distribution and proportion of reinforcing-phase particles in the matrix. The size, shape, and type of the ceramic reinforcement particles and the surfacing weld density significantly impacted the brittleness of the padded MMC layer. The fracture toughness increased upon decreasing the particle size of the hard reinforcing phase in the nickel alloy matrix and upon increasing the composite density. The calculated mean critical stress intensity factor KIc of the steel samples with deposited layers of cobalt alloy reinforced with TiC and PD-W particles was 4.3 MPa⋅ higher than that of the nickel alloy reinforced with TiC and WC-W2C particles.

Wear behaviour of Cr3C2–Ni cermet reinforced hardfacings

Submerged arc welding (SAW), plasma transferred arc welding (PTAW), and tungsten inert gas welding (TIG) technologies were used to produce austenitic stainless steel (SS) and nickel alloy (Ni) matrix based hardfacings without reinforcement and reinforced by Cr3C2–Ni cermet. As a substrate material normalized structural steel S355 has been chosen. Mechanical properties of produced hardfacings were assessed in terms of hardness (HV/30) and wear resistance tests. The latter property was analysed under different wear conditions: two-body (ASTM G132) and three-body (ASTM G65) abrasive wear tests. Microstructure and phase evolution were analysed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD), respectively. Cermet particles in all the conducted tests proved its’ selection – hardness and wear resistance of the reinforced hardfacings substantially increased. The addition of Cr3C2–Ni cermet increased the hardness twice on average in all utilized technologies leading to the higher wear resistance in further tests. Tendency of wear rate reduction is less expressed in SAW hardfacings, but in PTAW and TIG cases the strengthening effect is obvious: 8.6 and 8.1 times higher wear resistance of SS and Ni based PTAW hardfacings, respectively, and 7.5 and 4.8 times higher for TIG hardfacings. XRD analysis supported wear tests results proving the formation of the complex compounds.

Tribological properties of plasma-sprayed nickel alloy matrix self-lubricating coating at elevated temperatures

A nickel alloy matrix high-temperature self-lubricating coating (77.5 wt% (Ni–Cr–Mo–Al)–12.5 wt% Ag–10 wt% BaF2/CaF2) was prepared by plasma spraying technique. Results show that the Vickers microhardness of coating is (2.9 ± 0.5) GPa, and the average bonding strength is about (35.6 ± 0.5) MPa. The coating rubbing against Inconel 718 superalloy pin exhibits superior tribological performance with coefficient of friction (COF) of below 0.25 and wear rate of 8.2 × 10–5–15.2 × 10–5 mm3·N−1·m−1 at a wide temperature range from 25 to 800 °C, and the COF and the wear rate are slightly reduced with temperature increasing. The low COF and wear rate were attributed to the synergistic effects of Ag, BaF2/CaF2, Ag2MoO4 and BaMoO4.

Thermomechanical Wear Testing of Metal Matrix Composite Cladding for Potential Application in Hot Rolling Mills

Laser metal deposition (LMD) is utilized to clad the surface of a miniaturized test roll (Ø 40 mm) of tool steel. The cladding consists of two layers: a nickel alloy as intermediate layer deposited onto the surface of the steel substrate, and a metal matrix composite (MMC) as top layer consisting of spherical tungsten carbide particles embedded into the nickel alloy matrix. The thermomechanical wear behavior of the cladding is investigated on a test rig, where the test roll is pressed against an inductively heated load roll. Multiple test runs up to several hours simulating industrial loading conditions are performed. The presented testing procedure enables predicting the time‐dependent abrasive wear behavior of the cladding, in particular for hot rolling mill applications. After testing for 8 h at temperature of 650 °C and at contact pressure of approximately 1 GPa, the maximum depth of the wear mark is about 0.12 mm. Partial cracking, debonding and dissolution of the tungsten carbide particles, as well as formation of iron and chromium oxides at the surface of the wear marks occur. However, as low abrasive wear is observed, the investigated MMC may potentially be applicable for cladding rolls in steel hot rolling mills.

Influence of Mo and Al elements on the vacuum high temperature tribological behavior of high strength nickel alloy matrix composites

Abstract Vacuum along with high temperature is typical service condition for machinery components operated in aerospace. In this paper, the effects of Al and Mo elements on the mechanical and vacuum tribological properties of the nickel-alloy matrix solid-lubricating composites were investigated. Results presented that the increased addition of Al element noticeably improved the wear resistance and mechanical properties of the composites due to the formation of intermetallic in composites. While increasing content of Mo element means higher Vickers hardness and lower wear rate at low and moderate temperatures. The wear mechanism was proposed based on microstructure and compositions of sliding surface.

Microstructure, wear, and corrosion characterization of high TiC content Inconel 625 matrix composites

Titanium carbide/Inconel 625 (nickel alloy) metal matrix composites (MMCs) are developed for the combination of the super mechanical and corrosion properties of nickel alloy matrix and the high hardness of reinforcing titanium carbide particles (TiCp). The microstructure, hardness, wear, and corrosion behavior of MMCs with different volume contents of TiCp (25, 50 and 70vol.%) were investigated. The effect of increasing TiCp on the intermetallics and precipitates formed was examined using SEM/EDS and XRD analyses. The tribological behavior of the MMCs was investigated using wear testing with a pin-on-disk machine. The corrosion behavior was examined using potentiodynamic polarization experiments in 3% (w/v) NaCl solution. The results showed that the addition of TiCp into the Inconel 625 alloy resulted in formation of several intermetallics such as MoNi4, Cr2Ni3 and MoCr, in addition to molybdenum and chromium carbides in the matrix alloy. A great improvement in the hardness was resulted with addition of 25vol.% TiCp and consequently the wear resistance was also improved. Further increase of TiCp from 50 to 70vol.% did not result in more improvement of both hardness and wear resistance. The corrosion resistance of TiCp (25vol.%) composite was comparable to that of monolithic Inconel 625 matrix alloy, while clear reduction in the corrosion resistance was found in the 50 and 70vol.% composites.

In-situ synthesis of nanodiamonds reinforced iron-nickel matrix nanocomposites and their properties

In-situ synthesis of nanodiamonds (NDs) reinforced iron-30 wt% nickel (Fe30Ni) alloy matrix composites was achieved by spark plasma sintering (SPS) using Fe30Ni alloy powders added with carbon nanotubes (CNTs) from 0.25 to 1.0 wt%. The microstructures and properties of the composites were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, mechanical and coefficient of thermal expansion (CTE) tests. Experimental results showed that the NDs with mean size of 20 nm were generated with some residual CNTs remaining in the Fe30Ni matrix after the SPS processing at 1050 °C and 80 MPa. The resultant composites are NDs/CNTs hybrid reinforced metal matrix composite. The microhardness and compressive yield strength (σ0.2) of the Fe30Ni composites increased monotonically with the addition of CNT contents up to 0.75 wt%. The CTEs of the composites decreased substantially with the increase of CNT contents in temperature range of 25–150 °C. The Fe30Ni-0.75 wt% CNT is considered to be the optimal proportion of CNTs addition, in which the σ0.2 increased 23.4% and CTEs decreased 64.8%, respectively. The SPS provides a new method for the in-situ synthesis of nanodiamond reinforced metal matrix composites.

Influence of graphite content on the dry sliding behavior of nickel alloy matrix solid lubricant composites

Solid lubricant materials are promising for high performance machines and mechanical systems. In this paper, the nickel alloy matrix solid lubricant composites containing Ag, BaF2/CaF2 and three different amounts of graphite were prepared by hot pressed sintering method. The tribotests were performed sliding against Si3N4 ball in air from room temperature to 800°C. The effect of graphite content on the tribological behavior of the composites under high temperatures was studied. Micro-Raman, XRD and SEM analysis were used to analyze the morphologies and chemical composition of the worn surface and the wear mechanisms were also discussed.

High-temperature tribological behavior of a nickel alloy matrix solid-lubricating composite under vacuum

In aerospace, some moving parts will meet with simultaneous high temperature and vacuum environments. In this study, the tribological behavior of a nickel alloy matrix solid lubricant composite was contrastively investigated under both air and vacuum conditions from room temperature to 800°C. Results showed that both the friction coefficient and the wear rate of the composite were highly dependent on testing temperature and atmosphere. The friction coefficient in vacuum was lower than that in ambient air. The compositions of the frictional surfaces were analyzed, based on which, the mechanism of friction and wear was proposed.

Effect of Cryogenic Chill on Dendrite arm spacing, Ultimate tensile strength and Hardness of ASTM A 494 M Grade Nickel alloy Metal Matrix Composites

This paper describes the obtained results and the data withdrawn from the set of microstructure and mechanical properties of metal matrix composites developed using cryogenically cooled copper chills, consisting of ASTM A 494 M grade nickel alloy matrix and garnet particles as the reinforcement which was sand cast using a cryogenically cooled copper chill sides. The effect of cryogenic cooling rate on the dendrite arm spacing (DAS), ultimate tensile strength (UTS) and the Hardness were evaluated. It was found that the ultimate tensile strength is highly dependent on the rate of cryogenic effect and chilling which determines the dendrite arm spacing of the material. Attempts were also made in this paper to explain these effects and to correlate the UTS and hardness with DAS. Furthermore, it was found that UTS and Hardness increases as DAS decreases.

Lubricating behavior of adaptive nickel alloy matrix composites with multiple solid lubricants from 25 °C to 700 ºC

There is an increasing need to high temperature solid lubricant materials and techniques for moving system worked at high temperatures. In this study, the nickel alloy matrix composites with solid lubricants of Ag, CaF2 and MoS2 were fabricated by hot pressed sintering approach and their tribological properties in air from room temperature to 700ºC were investigated. Results indicated that the composites exhibited low friction coefficient of 0.16–0.40 and wear rate of (1–29.4)×10−5mm3N−1m−1. The favorable lubricating properties were attributed to the synergistic effect of the added solid lubricants and the oxide formed in situ on the worn surface.

Effect of Cryogenic Chill on Mechanical Properties of ASTM A 494 M Grade Nickel Based Alloy Metal Matrix Composites

An investigation in the present research was made to fabricate and evaluate the microstructure and mechanical properties of metal matrix composites developed using cryogenically cooled copper chills, consisting of ASTM A 494 M grade nickel alloy matrix and garnet particles as the reinforcement. The particle's amount added ranges from 3 wt. % to 12 wt. % in steps of 3%. A stir casting process was used to fabricate the composite. The matrix alloy was melted in a casting furnace at around 1350˚C, the garnet particulates preheated to 600˚C, were introduced into the molten metal alloy. When pouring melt into mould, an arrangement was made at one end of the mould by placing copper chill blocks of varying thickness brazed with MS hallow block in which liquid nitrogen was circulated simultaneously for cryogenic effect. After solidification produced composite materials thus synthesized were examined for microstructural and mechanical properties as per ASTM standards.

Action of Cryogenic chill on Mechanical properties of Nickel alloy Metal Matrix Composites

In the area of material science engineering, metallurgists may be at the forefront of new technologies, developing metals for new applications, or involved in the traditional manufacture. By doing so it is possible for metallurgist to apply their knowledge of metals to solve complex problems and looking for ways to improve the mechanical properties of the materials. Therefore, an investigation in the present research was made to fabricate and evaluate the microstructure and mechanical properties of composites developed using cryogenically cooled copper chills, consisting of nickel alloy matrix and garnet particles as the reinforcement. The reinforcement being added ranges from 3 to 12 wt.% in steps of 3%. A stir casting process was used to fabricate the nickel base matrix alloy fused with garnet reinforcement particle. The matrix alloy was melted in a casting furnace at around 1350°C, the garnet particulates which was preheated to 600°C, was introduced evenly into the molten metal alloy. An arrangement was made at one end of the mould by placing copper chill blocks of varying thickness brazed with MS hallow block in which liquid nitrogen was circulated for cryogenic effect. After solidification, the composite materials thus synthesized were examined for microstructural and mechanical properties as per ASTM standards.

Studies on the Codeposition of SiC Nanopowder with Nickel, Cobalt, and Co-Ni Alloys

Electrodeposition of SiC nanopowder (approximately 120 nm) with nickel, cobalt, and Co-Ni alloy matrix was studied. It was found that particles suspended in the bath affect slightly the reduction of metallic ions. Incorporation of the ceramic particles was governed mainly by the morphology of the matrix surface, while no strict correlation between the amount of cobalt ions adsorbed on the powder and the SiC content in the composites was found. Microhardness of nickel deposits was 585±5 HV, while for cobalt-rich coatings (84–95 wt.% Co) the values were in the range of 260–290 HV, independently of the SiC content in the coatings. Fine-grained nickel deposits were characterized by good corrosion resistance, while cobalt and Co-Ni alloys showed high corrosion current densities.

Development of self-lubricating composite materials of nickel with molybdenum disulfide, graphite and hexagonal boron nitride processed by powder metallurgy: preliminary study

The purpose of this work was to develop nickel self-lubricating composites using solid lubricant as second phase and obtained by powder metallurgy. The work involved the study of chemical stability and chemical interaction between the nickel alloy matrix and solid lubricating additives (molybdenum disulfide, graphite and hexagonal boron nitride). The results showed a thermodynamic stability during sintering for the composites containing the phases of graphite and hexagonal boron nitride. The presence of molybdenum disulfide phase permits a reaction with the matrix, the formation of a liquid phase of nickel sulfide and the solubilization of molybdenum in the matrix.

Microstructure and failure modes during scratch testing of laser cladded WC–NiCrBSi coatings with spherical and angular carbides

Laser cladded coatings have been used extensively to extend the service life of components exposed to severe abrasive wear. One of the main wear resistant materials used in laser cladding is ceramic–metallic composite. Despite extensive use of this class of material, there is very limited knowledge regarding mechanical degradation mechanisms, such as cracking and plastic deformation, under different wear conditions. In this investigation a mixture of nickel alloy and tungsten carbide powders were used to deposit the coating. Two types of tungsten carbide powders with spherical and angular carbides were employed. The microstructures of the coatings were analysed thoroughly by optical microscopy, electron probe microanalysis and wavelength dispersive spectrometry. Failure and cracking mechanisms of laser cladded coatings under normal and tangential loading were systematically investigated using scratch testing. In the nickel alloy matrix, fine mixed secondary carbides were formed due to partial dissolution and formation of the secondary tungsten carbide during laser cladding. These secondary carbides were rich in chromium, tungsten and nickel and had a blocky and/or bar-like shape. Failure mechanisms associated with scratch testing were dependent on the microstructure and carbide morphology, applied stress and location of carbide particles with regard to the scratch groove. Owing to the high binder mean free path between the carbide particles, plastic deformation of the binder was the dominant failure mechanism. Additionally, partial or whole fragmentation of carbides, carbide/binder interface cracking and limited binder fracture were observed.

Theoretical and practical approaches to creep of Waspaloy

After normalising the applied stress through the ultimate tensile strength at each creep temperature, the creep and creep fracture properties of Waspaloy at 873 to 1023 K are superimposed onto ‘master curves’ using an Arrhenius term containing the activation energy for lattice diffusion in the nickel alloy matrix (~276 kJ mol−1). In this way, straightforward approaches are introduced for extrapolation of short term property sets, aiming to minimise the scale of the protracted test programmes currently needed to provide long term engineering design data. The observed behaviour patterns are then interpreted by clarifying the deformation and damage processes governing the changing shapes of the creep strain–time curves exhibited as the test conditions are varied.

Calorimetric Studies of Dissolution Kinetics of Ni<sub>2</sub>(Cr,Mo) Phase in Ni-Cr-Mo Alloys Using Non-Isothermal Approach

The kinetics of dissolution of ordered phase with Pt2Mo structure has been studied in two nickel chromium alloys – one without molybdenum and another with molybdenum - using differential scanning calorimetry. The activation energy for dissolution, determined using three nonisothermal approaches was found to be ~ 418 kJ /mole for both the alloys. This value agreed very well with the activation energy for coarsening of g″ precipitates in Ni-Cr-Mo matrix and is close to activation energy for mobility of chromium and molybdenum in complex nickel alloy matrix.