Wear Resistance Of Mg Alloy Research Articles

A review on wear resistance of Mg alloys: the influence of common rare earth alloying elements and general modification techniques

A review on wear resistance of Mg alloys: the influence of common rare earth alloying elements and general modification techniques

Influence of Interlayers on Adhesion Strength of TiN Film on Mg Alloy

The wide application of Mg alloys has been restricted because of their poor corrosion and wear resistance. Titanium nitride ceramic films prepared via magnetron sputtering can improve the corrosion and wear resistance of Mg alloys. However, residual stress produced at the interface between the film and the Mg alloy substrate causes the TiN film to spall off and reduces its service life. One potential approach to mitigating residual stress involves enhancing the adhesive strength between the film and the substrate, thereby potentially extending the service life of the film. To increase the adhesion strength between the TiN film and the Mg alloy substrate, a Ti or Al interlayer was deposited on the Mg alloy by magnetron sputtering. Subsequently, the adhesion strengths of TiN/Ti and TiN/Al were determined under a single high shear force by scratch tests and were determined under multiple low shear forces by friction and wear tests. The results of scratch tests show that TiN with the Ti interlayer on the Mg alloy substrate has superior adhesion strength under a single high shear force. And the results of friction and wear tests show that both the TiN/Al and TiN/Ti films provided protection to the Mg alloy substrate against friction and wear, and TiN with the Ti interlayer on the Mg alloy substrate has superior adhesion strength under multiple low shear forces. This work can provide guidance for the selection of interlayers between Mg alloy substrates and hard ceramic films.

Improving the wear resistance of the magnesium alloy WE43 by cold sprayed Ni–Al2O3 and Ni–Zn–Al2O3 coatings

Abstract Lightweight magnesium (Mg) alloys are employed in a wide range of applications due to their high specific strengths. Nevertheless, some applications require improvement of the wear resistance of Mg alloys. The purpose of this study was to investigate the effect of the initial surface conditions, cold spray temperature, and coating material on the wear resistance of the cold sprayed coatings on WE43 Mg substrate. Blasted and sandpapered surfaces were coated with commercial powders of K-32 (Ni and Al2O3) and K-714 (Zn, Ni, and Al2O3). The coating materials were cold sprayed on blasted and sandpapered WE43 Mg surfaces at 500 °C and 600 °C. Surface roughness, thickness and wear resistance of the coatings were examined. Deposition efficiency was improved by raising the N2 gas temperature. The samples with the greatest wear resistance were those that were coated with Zn, Ni, and Al2O3 powder mixture on sandpapered surfaces at temperatures of 600 °C, where deposition efficiency is maximum. Cold spray coatings enhanced the wear resistance of the WE43 Mg substrate.

Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications

Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.

Al2O3 eliminating defects in the Al coating by laser cladding to improve corrosion and wear resistance of Mg alloy

AbstractAlthough Al produces a solid metallurgical bonding with Mg alloy substrates, micropores or crevices in the Al coating can reduce the resistance of Mg alloy to corrosion. In this study, a composite coating with a defect‐free microstructure was prepared on the AZ31 Mg alloy substrate by introducing Al2O3 into the Al matrix via the method of laser cladding. On the one hand, Al2O3 with thermal insulation had a low thermal expansion coefficient and was not very prone to voids during laser melting. On the other hand, Al2O3 particles with a small size acted as the filler in the micropores or crevices. The Al/Al2O3 coating exhibited a smaller current density (2.1 × 10−6 A/cm2) in comparison with those of bare substrate and Al coating (158.4 × 10−6 and 3.1 × 10−6 A/cm2, respectively), which was mainly ascribed to the pore‐free microstructure and high resistance to corrosion of Al2O3 phase. A favorable microhardness value of 95.3 HV was achieved for Al/Al2O3 coating, approximately 1.8 times higher than that of Al coating (52.8 V), which was mainly ascribed to the dispersion hardening of Al2O3 phase. Meanwhile, the Al/Al2O3 coating significantly reduced wear volume from 2.8 mm3/m of Al coating to 0.4 mm3/m, showing great potential for weight reduction applications.

Enhanced Electrochemical and Tribological Properties of AZ91D Magnesium Alloy via Cold Spraying of Aluminum Alloy

Magnesium (Mg) alloys have remarkable physical and mechanical properties for various aerospace applications. However, the high corrosion susceptibility and low wear resistance of Mg alloys restrict their wider use. To overcome these problems, 6061 Al alloy coatings were fabricated via the cold spraying process on the AZ91D Mg alloy substrate and a detailed comparative study on the wear and corrosion properties was carried out. The microstructure analysis of the compact coatings revealed low porosity with no phase change during the deposition process. The coatings showed improved corrosion resistance up to seven times as confirmed by potentiodynamic polarization and electrochemical impedance spectroscopy measurements in 3.5 wt.% NaCl aqueous solution. The as-deposited coatings were also compared with commercial bulk alloys of similar composition for their suitability to industrial applications. The tribological behavior of the coatings and substrate was investigated using tribometer. The wear resistance of the coatings improved more than two orders of magnitude as compared to the substrate. Abrasive and oxidative wear mechanisms were dominant in the coatings and substrate. The results showed that cold spraying of 6061 Al alloy on AZ91D Mg alloy could be an auspicious process to overcome the poor corrosion and wear resistance of this Mg alloy for practical industrial applications.

Enhanced corrosion resistance of biodegradable Mg alloys via ultrasonically treated fluoride coating

Magnesium (Mg) and its alloys are promising materials for use in medical applications due to their good mechanical properties, biocompatibility, and biodegradability. However, the rapid corrosion of Mg alloys restricts their range of use in these applications. Fluoride conversion (HF) coating is one of the most effective and environmentally friendly surface modifications available to address this limitation. The formation of a thin, uniform, smooth, and adherent fluoride coating improves the corrosion and wear resistance of Mg alloys. However, this method is not suitable for long-term medical treatment. In previous research, we found that ultrasonically treated fluoride (HFU) coatings can increase the corrosion resistance of Mg alloys. The aim of this study, therefore, was to investigate in more detail the surface morphology, coating thickness, composition, and corrosion of ultrasonically treated fluoride-coated Mg alloys. The results indicated that the HF and HFU coatings were identical in terms of thickness and composition. However, unlike the HF-coated specimens, there were no pores and cracks on the surface of the HFU-coated specimens, which also exhibited significantly higher corrosion resistance in electrochemical corrosion and mass loss tests. As a result, HFU-coated Mg alloys may prove suitable for use in long-term medical treatment.

Effect of recovery treatment on the wear resistance of surface hammered AZ31 Mg alloy

Surface severe plastic deformation (SPD) is an approach used to nanocrystallize metallic surfaces for enhanced resistance to wear. However, SPD alone does not generate well-defined nanocrystalline structure but one consisting of nano-sized dislocation cells with diffuse boundaries. For materials with limited slip systems such as Mg, SPD may harden the materials but deteriorate their fracture toughness. As a result, the benefit of SPD to the wear resistance of materials may not be appreciable. In this study, we nanocrystallized the surface layer of AZ31 Mg alloy by repeated hammering, followed by recovery treatment (HR). The microstructure, wear behavior, grain structure and wear debris of differently treated samples, including hammering (HM), hammering plus recovery treatment (HM-R), and as-received, were investigated and compared. Results of the study show that the SPD-HR sample had a superior nanocrystalline surface exhibiting the highest wear resistance. The hammered sample (HM) was harder than the HM-HR one but its wear resistance is lower than that of the latter, though it still performed better than the as-received one. The wear debris analysis showed that the surface of the HM-R sample was tougher than that of the HM one. The observed phenomena indicate that the wear resistance of AZ31 Mg alloys depends on both hardness and toughness to which the ductility is of importance. The recovery treatment after HM certainly helped achieving well-defined nanocrystallization for improved wear resistance of the Mg alloy.

Investigation of tribological properties of micro-arc oxidation ceramic coating on Mg alloy under dry sliding condition

To enhance wear resistance of Mg alloy, micro-arc oxidation (MAO) ceramic coatings on Mg substrate were prepared in silicate electrolyte under various currents. It was found that the surface roughness and thickness of MAO coating were increased with the increase of current. The dry tribological tests showed that the friction coefficient and wear resistance of thicker coatings (obtained under currents of 3 A and 4 A) were much higher than that of Mg alloy and the thin coating (obtained under current of 2 A), meanwhile the lifetime of the coating obtained under 4 A was longer than the other coatings under higher load. The wear type of thin MAO coating was slight abrasive wear under low load, whereas translated to severe adhesive wear under high load. While the main wear mechanism of thick MAO coating was slight abrasive wear or scratch under the given test condition, which was attributed to the thick intermediate layer improved load support for the soft substrate. The tribological study indicated that the MAO coating obtained under 4 A current had better wear resistance and life time due to its compact microstructure and thickness.

Effect of wear parameters on dry abrasive wear of RZ5-TiC in situ composite

PurposeThe purpose of this study is to increase the wear resistance of Mg alloy by adding hard ceramic particles to it. The inclusion of hard ceramic particles further strengthen the Mg alloy, resulting in higher wear resistance. Mg alloys containing Zn, rare earth and Zr exhibit high specific strength and excellent creep resistance, making them suitable for aerospace components such as aircraft gearboxes and generator housings.Design/methodology/approachIn the present study, composites have been produced in situ by using RZ5 mg alloy as matrix and TiC as reinforcement by self-propagating high-temperature synthesis technique. The abrasive wear behavior of RZ5 Mg alloy matrix reinforced with TiC particulates has also been examined. The pin-on-disc apparatus has been used for the tests. The abrasive paper is used as a counter body, and the results are obtained by changing sliding distance and applied load.FindingsA notable enhancement in the wear resistance and mechanical properties of tested composite has been observed as compared to the RZ5 Mg alloy as a matrix. There is a uniform increment in the change in weight loss of RZ5-TiC composite with increasing sliding distance and applied load, but it decreases with increasing TiC content. The coefficient of friction (µ) also decreases uniformly with an increase in the reinforcement of TiC, but it decreases with an increase in applied load and sliding distance. The investigation of the worn composite, which determines dominant wear mechanisms as abrasion and plowing grooves on tested samples, has been done using field emission scanning electron microscopy.Originality/valueThe current manuscript provides a detailed abrasive wear analysis of RZ5-TiC composite by using different wear parameters. Specifically, extensive experimental data have been provided for RZ5-TiC composite. The effects of parameters such as applied load, sliding distance and Wt.% of TiC on the weight loss and coefficient of friction of the composites have been analyzed and discussed thoroughly.

Structure and properties of newly designed MAO/TiN coating on AZ31B Mg alloy

A duplex MAO/TiN coating was fabricated on AZ31B Mg alloy through micro-arc oxidation (MAO) followed by a multi-arc ion plating (M-AIP) process. The structure, composition, and corrosion resistance of these coated samples were evaluated using SEM, EDS, XRD, and electrochemical methods. The results showed that the porous MAO layer was effectively sealed by the M-AIP layer, indicating that the MAO layer can act as an interlayer to offer an inert rough surface and necessary hardness for the Mg alloy to bond with the M-AIP layer (especially for a hard coating such as TiN). The MAO/Ti-coated samples exhibited the worst corrosion resistance and lower hardness compared with the MAO-coated samples, while the MAO/TiN coating provided higher corrosion resistance and hardness. It can be speculated that unavoidable defects such as pores and cracks are responsible for the poor properties. Although the MAO layer was demonstrated to improve the interfacial compatibility between the hard coating and the soft substrate, a compact and dense hard coating is still essential to ensure the corrosion and wear resistance of Mg alloys.

Wear behaviour of plasma electrolytic oxide coatings on E21 and WE43 Mg alloys

Plasma electrolytic oxidation (PEO) is a promising and environmentally friendly surface treatment based on electrolytic conversion that forms a protective ceramic oxide coating on light alloys. The PEO coating provides excellent corrosion and wear resistance to the substrate and, as such, is being considered for wider industrial applications on Mg alloys, which are commonly used in aerospace and automotive industries. Several studies have been conducted on the PEO process of conventional Mg alloys, such as AZ and AM series alloys, but to date, little has been reported on rare earth (RE) element containing Mg alloys. In this study, RE elements containing E21 and WE43 Mg alloys were coated using a laboratory scale PEO system. In order to enhance the frictional properties, the surface of PEO coatings was post-treated with MoS2 lubricant. Test results indicated that the PEO coating significantly enhanced the wear resistance of Mg alloys. Further improvement in wear resistance was achieved by the lubricant top layer.

Influence of nano-SiC on microstructure and property of MAO coating formed on AZ91D magnesium alloy

Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate–aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, element composition and hardness of the coatings were respectively investigated by scanning electron microscopy(SEM), film thickness meter, X-ray diffraction (XRD), energy disperse spectroscopy(EDS) and Vickers hardness tester. The wear resistance of Mg alloy and coatings were evaluated by friction and wear apparatus, while the corrosion resistance of Mg alloy and coatings were evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The results show that after adding nano-SiC into the electrolyte, both the striking voltage and final voltage decrease, the size and number of the micropore on the surface of the coating decrease, the thickness and hardness of the coating increase, both the wear resistance and corrosion resistance of the coating raise.

Wear behaviours of Pb added Mg–Al–Si composites reinforced with in situ Mg2Si particles

In this study, the effect of adding Pb at different ratios on the wear resistance of Mg alloys reinforced with low density “in situ” Mg2Si particles has been investigated. Pb, at a rate of 0.2%, 0.5%, and 1%, was added to Mg–10% Al–12Si alloys reinforced with “in situ” particles, produced from the reinforcement nucleation within the matrix. The microstructure characterisation and wear properties of alloys, produced using a casting method was examined. Light Optical Microscopy (LOM), X-ray Diffraction (XRD) analyses and a Scanning Electron Microscope (SEM) were used to conduct the microstructure characterisation. A pin-on-disc type wear device, under different loads and different sliding distances, was used to conduct the dry environment wear experiments carried out for investigated alloys. Microstructure analysis concluded that Mg2Si particles formed, and that an Mg17Al12 intermetallic phase was present in the structure. The Pb added to the alloys decreased the wear resistance of the alloy.

Tribological properties of plasma electrolytic oxide coatings on magnesium alloys

Plasma electrolytic oxidation (PEO) is a promising and environmentally friendly surface modification process free of Cr+6 and heavy metals. The process forms a protective and well adhered ceramic coating on valve metals such as Mg, Al and Ti. In this study, AZ91D and AM60B Mg alloys commonly used in automotive and aerospace industries were surface treated using an industrial scale PEO system in a KOH–Al2O3 based alkaline electrolyte. PEO coatings of two different nominal thicknesses, i.e. 10 μm (K10) and 25 μm (K25), were obtained. The microstructure and phase composition of the PEO coatings were analysed using scanning electron microscopy and X-ray diffraction respectively. Scratch tests were carried out to determine the adhesion strength of the PEO coatings. The tribological behaviour of PEO coatings under dry sliding conditions against 100Cr6 steel ball was investigated using the ball-on-plate test configuration. Test results indicated that the PEO coatings significantly enhanced the wear resistance of Mg alloys with increasing coating thickness. For uncoated Mg plates, abrasive and adhesive wear mechanisms acted together during sliding motion, while no predominant wear mechanism was seen for PEO coated alloys.

Improved corrosion and wear resistance of Mg alloys via laser surface modification of Al on AZ31B

A highly intense laser beam from a continuous wave diode-pumped ytterbium laser source was used to synthesize a corrosion and wear resistant aluminum coating rich in Al 12Mg 17 intermetallic phase by direct melting of aluminum precursor powders on AZ31B Mg alloy substrates. The coating composition and microstructure were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high resolution energy diffraction spectroscopy in a transmission electron microscope. From X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy diffraction spectroscopy analysis it was confirmed that laser processing resulted in uniform distribution of a highly corrosion resistance Al 12Mg 17 intermetallic phase within the coating. The effect of this type of coating on the corrosion and wear resistance of the Mg alloy is investigated in the current study. Under the set of laser processing parameters employed in the current work, no significant change in microstructural and phase evolution and thereby corrosion and wear performance was observed for the laser processed samples. In general improved corrosion resistance was observed for the laser processed samples as compared to the untreated AZ31B. Also, as the precipitation of an intermetallic phase is expected to strain harden the matrix, an improvement in dry sliding wear was observed for the laser processed samples.

Structure and wear resistance of TiN and TiAlN coatings on AZ91 alloy deposited by multi-arc ion plating

In order to investigate the microstructure of TiN and TiAlN coatings and their effect on the wear resistance of Mg alloy, TiN and TiAlN coatings were deposited on AZ91 magnesium alloy by multi-arc ion plating technology. TiN and Ti 70Al 30N coatings were prepared on the substrate, respectively, which exhibited dark golden color and compact microstructure. The microstructures of TiN and Ti 70Al 30N coatings were investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The micro-hardness and wear resistance of TiN and Ti 70Al 30N coatings were investigated in comparison with the uncoated AZ91 alloy. The XRD peaks assigned to TiN and TiAlN phases are found. The hardness of TiN coatings is two times as high as that of AZ91 alloy, and Ti 70Al 30N coating exhibits the highest hardness. The wear resistance of the hard coatings increases obviously as result of their high hardness.