Tribological behavior of AZ91D magnesium alloy composite: effect of hybrid WC – SiO2 nanoparticles

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Fahad ◽  
Bavanish B.
Keyword(s):  
Magnesium Alloy ◽  
Wear Rate ◽  
Az91d Alloy ◽  
Hybrid Particles ◽  
Wear Properties ◽  
Sliding Speed ◽  
Composite Effect ◽  
Content Type ◽  
Climate Conditions ◽  
Az91d Magnesium Alloy

Purpose Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO2). Design/methodology/approach In this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO2 and AZ91D – (WC + SiO2) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus. Findings Results showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO2 particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO2) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO2 particles. Hence, the proposed AZ91D – (WC + SiO2) composite could be a suitable candidate to be used in the aviation applications. Originality/value This work is original which deals with the effect of hybrid particles, i.e. WC and SiO2 on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.

Tribological and ageing behavior of Az91D magnesium alloy fortified with nano lanthanum and nanoceria by stir casting for aviation application

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Fahad ◽  
Bavanish B.
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Magnesium Alloy ◽  
Cerium Oxide ◽  
Stir Casting ◽  
Cerium Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Az91d Alloy ◽  
Content Type ◽  
Az91d Magnesium Alloy

Purpose The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve the lifetime of aircraft. Hence, it is vital to enhance the wear resistance and strength of the material. Design/methodology/approach In this investigation, the Az91D magnesium alloy was reinforced with lanthanum (La2O3) and cerium oxide (CeO2) nanoparticles by stir casting and heat treatment process and the tribological and mechanical properties were analyzed. Findings The results showed the Az91D/CeO2 composite exhibited higher density (1.96 g/cm3) and lower porosity (1.01%) compared to other materials due to the diffusion of CeO2 nanoparticles in between the atoms of Az91D alloy. The hardness of Az91D/ CeO2 & Az91D/ La2O3 was improved by 38% and 34%, respectively, compared to Az91D alloy owing to the reinforcing effect of hard nanoparticles. Further, the inclusion of nanoparticles decreased the mass loss and showed lower wear rate compared to the Az91D alloy due to the pinning effect of nanoparticles. In addition, the friction coefficient was observed in the order of Az91D > Az91D/ La2O3 > Az91D/ CeO2. Moreover, the heat treatment displayed positive results on the properties of all the materials. Originality/value This work is original as the combination of cerium oxide nanoparticles with Az91D magnesium alloy is not tried by earlier investigators. Further, the comparative performance of both lanthanum and cerium oxide nanoparticles on the tribological and mechanical behavior of Az91D alloy has been analyzed for aviation application. This study will provide new information to the scientific world to increase the lifetime of aviation structures.

Research on the delamination wear properties of the pure carbon strip at the high-sliding speed with electric current

2018 ◽  
Vol 70 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Hongjuan Yang ◽  
Lin Fu ◽  
Yanhua Liu ◽  
Weiji Qian ◽  
Bo Hu
Keyword(s):  
Electric Current ◽  
High Speed ◽  
Normal Load ◽  
Copper Wire ◽  
Electrical Current ◽  
Wear Properties ◽  
Sliding Speed ◽  
Content Type ◽  
Delamination Wear ◽  
High Speed Data

Purpose This paper aims to investigate the delamination wear properties of a carbon strip in a carbon strip rubbing against a copper wire at the high-sliding speed (380 km/h) with or without electrical current. Design/methodology/approach The friction and wear properties of a carbon strip in a carbon strip rubbing against a copper wire are tested on the high-speed wear tester whose speed can reach up to 400 km/h. The test data have been collected by the high-speed data collector. The worn surfaces of the carbon strip are observed by the scanning electron microscope. Findings It was found that there was a significant increase of the delamination wear with the decrease of the normal load when the electric current is applied. The size of the flake-like peeling also increases with the decrease of normal load. The delamination wear extends gradually from the edge of the erosion pits to the surrounding area with the decrease of the normal load. However, the delamination wear never appears in the absence of electric current. It is proposed that the decreased normal load and the big electrical current are the major causes of the delamination wear of the carbon strip. Originality value The experimental test at high-sliding speed of 380 km/h was performed for the first time, and the major cause of the delamination was discovered in this paper.

Wear Characteristics of Bulk Ti3AlC2 under Current-Carrying Conditions

2007 ◽  
Vol 561-565 ◽  
pp. 563-566
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Hua Zhang ◽  
Hong Bing Zhang
Keyword(s):  
Wear Rate ◽  
Low Carbon Steel ◽  
Normal Pressure ◽  
Mechanical Effect ◽  
Low Carbon ◽  
Wear Properties ◽  
Sliding Speed ◽  
Wear Characteristics ◽  
Friction Tester ◽  
Iron Titanate

The current-carrying wear characteristics of Ti3AlC2 sliding against low-carbon steel were investigated. Tests were carried out using a block-on-disk type friction tester, with sliding speeds of 20~60 m/s, normal pressures range in 0.4~ 0.8 MPa, and the current intensity of 0 A, 50 A and 100 A. The Ti3AlC2 showed good current-carrying wear properties. At the sliding speed of 20 m/s, the wear rate of the Ti3AlC2 (× 10-6 mm3/Nm) was varied in the range of (2.05 ~ 2.41), (2.64 ~ 2.39) and (6.26 ~ 3.62), under the current of 0 A, 50 A and 100 A, respectively. Both the surfaces of Ti3AlC2 and the steel were covered by a frictional film, which was consisted of iron titanate (Fe2.25Ti0.75O4) and aluminum iron oxide (AlFeO3). The wear rate of Ti3AlC2 with current was composed of two parts: the interaction of micro-arc ablation and mechanical friction, and the coupled action of thermal and mechanical effect. Which one will be the main mechanism depends on the material parameters of Ti3AlC2 and the mechanical parameters such as the normal pressure or the sliding speed.

Corrosion Resistance of the Ceramic Coating Formed by Micro-Plasma Arc Oxidation on AZ91D Alloy

2007 ◽  
Vol 336-338 ◽  
pp. 2451-2453
Author(s):  
Shu Hua Li ◽  
Fu Chi Wang
Keyword(s):  
Magnesium Alloy ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Az91d Alloy ◽  
Plasma Arc ◽  
X Ray Diffraction ◽  
Compact Layer ◽  
Az91d Magnesium Alloy ◽  
Loose Layer ◽  
Salt Fog

The ceramic coating was formed by micro-plasma arc oxidation (MPAO) on AZ91D magnesium alloy. The surface and section morphology of coatings were observed using scanning electron microscopy. The phase composition of coatings was analyzed by X-ray diffraction. The method of salt fog experimental was carried out to proof-test performances of anti-corrosion of material. The results showed that the ceramic coating was composed by loose layer and compact layer. The coating surface has a large number of grains with various sizes. In addition, there is also a lot of pore in the loose layer, but the compact layer is tighter than the loose layer. Compact layer has a good combination with substrate magnesium alloy. The MPAO coating is mainly composed of silica oxide (MgAl2Si3O12 and β-Mg2SiO4 and (Mg4Al14) (Al4Si2)O20) and composite oxide of Mg and Al (δ-MgAl28O4). The performance of resistant corrosion of AZ91D coved by ceramic coating is higher than AZ91D magnesium alloy. The corrosion ratio of AZ91D alloy coved by ceramic coatings to AZ91D alloy is 1:8.61.

Effects of welding speeds on the microstructural and mechanical properties of AZ91D Mg alloy by friction stir welding

2020 ◽  
Vol 11 (6) ◽  
pp. 769-782 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Base Material ◽  
Welding Parameters ◽  
Content Type ◽  
Friction Stir ◽  
Az91d Magnesium Alloy ◽  
Transverse Tensile

PurposeThe main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.Design/methodology/approachMicrostructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.FindingsMetallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.Research limitations/implicationsIn the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.Practical implicationsMagnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.Originality/valueLimited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

Influence of β-Mg17Al12 Phase on Initial Pitting Process of AZ91D Magnesium Alloy

2016 ◽  
Vol 879 ◽  
pp. 1895-1898 ◽  
Author(s):  
Masahiro Kaido ◽  
Kenta Imai ◽  
Masahiko Hatakeyama ◽  
Satoshi Sunada
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Az91d Alloy ◽  
Az91d Magnesium Alloy ◽  
Β Phase ◽  
Α Phase ◽  
Before And After ◽  
Sem Micrograph ◽  
Chloride Environment ◽  
Z Contrast

AZ91D magnesium alloy for casting is significantly corroded in chloride environment. In addition, Al-rich-α phase, which is formed during cooling process around β-Mg17Al12 phase, is one of the important factors on corrosion behavior in AZ91D. It is expected that pitting formation is dominant in the corrosion behavior in magnesium alloys. To clarify the influence of the Al-rich-α phase to pitting formation and corrosion behavior in AZ91D alloy, we have investigated the relationship between Microstructure and pitting formation in this study. We have carried out polarization curve measurement and scanning electron microscope (SEM) observation before and after the corrosion-tests. SEM micrograph of as-cast samples showed AZ91D alloy consist of α phase, Al-rich-α phase which shows bright Z-contrast due to high Al contents and β phase. Al-rich-α phase formed around β phase. After the corrosion examination, holes were observed at Al-rich-α phase around the β phase, and it is thought that small pits grow up to be holes, because β phase is remained, while the Al-rich-α phase around the β phase preferentially dissolves with time. The result indicates that Al-rich-α phase around β phase enhance the formation of pitting and preferentially dissolve it in initial stage of corrosion in AZ91D alloy.

Effect of Rare Earth Elements on Microstructure and Mechanical Properties of AZ91D Alloy

2014 ◽  
Vol 960-961 ◽  
pp. 87-91
Author(s):  
Zhi Chao Liu ◽  
Yao Li ◽  
Jun Jie Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Az91d Alloy ◽  
Resistance Furnace ◽  
Moderate Amount ◽  
Az91d Magnesium Alloy ◽  
Performance Decline ◽  
Rare Earth Content

Rare earth Y、Gd、Nd were added to improve the tensile strength, elongation, hardness and microstructure of AZ91D magnesium alloy in this study. The investigation had been undertaken by 8 GWU type resistance furnace, RGM - 50 electronic machine , Vickers ,etc. Results show that a moderate amount of composite adding rare earth can effectively improve the tensile strength of AZ91D alloy, elongation, hardness and the organizational structure, as a rare earth content increased after the first performance decline. When rare earth content is 1.8%, the highest tensile strength up to 276.58mpa, 8.3% elongation. When rare earth content is 2.4%, the hardness is up to 99.36 HV1.96.

Protective Ability of Graphite Powder on Molten AZ91D Magnesium Alloy

2017 ◽  
Vol 898 ◽  
pp. 111-117 ◽  
Author(s):  
Wei Hong Li ◽  
Ji Xue Zhou ◽  
Bai Chang Ma ◽  
Jian Hua Wu ◽  
Jin Wei Wang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Low Cost ◽  
Energy Dispersive Spectrometer ◽  
Graphite Powder ◽  
Ambient Atmosphere ◽  
Surface Films ◽  
Az91d Alloy ◽  
Az91d Magnesium Alloy ◽  
Protective Ability ◽  
Protection Method

Graphite powder was used to prevent a molten AZ91D magnesium alloy from oxidation and burning in order to develop a new pollution-free protection method with low cost. The protection method is expected to have good protective effect without decreasing the mechanical properties of the alloy. The protective ability of graphite powder on the alloy was investigated. Experimental results showed that graphite powder could protect AZ91D melt. The protective ability increased with graphite powder amount and decreased with holding time. The microstructure, chemical composition and phase composition of the surface films formed on the molten AZ91D alloy were analyzed using scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction, respectively. The protection mechanism was discussed. The surface films produced by the reactions between graphite powder, AZ91D alloy melt and the ambient atmosphere had two layers. The continuous and compact outer layer, mainly consisting of MgO and C, may be the fundamental reason for the fact that graphite powder could protect AZ91D alloy melt.

Dry sliding tribological properties of A356-SiCP aluminum matrix composites prepared by vacuum stir casting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiaqi Pan ◽  
Xiaoshan Liu ◽  
Guoqiu He ◽  
Bin Ge ◽  
Peiwen Le ◽  
...  
Keyword(s):  
Wear Rate ◽  
Tribological Properties ◽  
Aluminum Matrix ◽  
Stir Casting ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Particle Content ◽  
Sliding Speed ◽  
Content Type ◽  
Casting Technique

Purpose The purpose of this paper is to understand the effect of particle content, applied load and sliding speed on the tribological properties of A356-SiCP composites manufactured using a newly developed vacuum stir casting technique. Design/methodology/approach A356 alloy reinforced with 10, 15 and 20 vol% SiC particles was prepared by vacuum stir casting. Tribological tests were carried out on block-on-ring tribometer under dry sliding conditions, room temperature. Wear mechanism was investigated by scanning electron microscope and energy dispersion spectrum. Findings SiCP is homogeneously dispersed in the matrix. The increase in SiCP content decrease wear rate, but it leads to an increase in coefficient of friction. The wear rate increase and friction coefficient present different variation trends with increasing load. For A356-20%SiCP composite, when the load is less than 10 MPa, wear rate and friction coefficient under sliding speed of 400 rpm are lower than those of 200 rpm. Wear mechanism transition from abrasion, oxidation, delamination, adhesion to plastic flow as load and sliding speed increasing. Practical implications Results of this study will help guide the use of A356-SiCP in many automotive products such as brake rotors, brake pads, brake drums and pistons. Originality/value There are few paper studies the effect of particle content, applied load and sliding speed on the tribological properties of A356-SiCP composites. Aluminum matrix composites with uniform distribution of reinforcing particles were successfully prepared by using the newly developed vacuum stir casting technique.

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