Dry Sliding Wear Behavior of Ti–6Al–4V Implant Alloy Subjected to Various Surface Treatments

Titanium alloys are extensively used in various fields of engineering, medicine, aerospace, marine due to their excellent mechanical properties. Their usage is more pronounced today in the field of biomedical implants due to superior biocompatibility, corrosive resistance and high strength. However, titanium alloys have poor wear resistance due to high coefficient of friction. Poor abrasive wear resistance results in the formation of wear debris at the implant area causing toxicity, inflammation and pain. Surface treatment of the implant alloy through heat treatment, application of protective coatings and introduction of compressive residual stresses by shotpeening are some of the methods to mitigate wear of the implant alloy. In this work Ti?C6Al?C4V implant alloy is treated under various conditions of heat treatment and shotpeening operations on a pin on disc wear testing machine. Scanning electron micrograph along with energy dispersive spectrometry analysis is done to authenticate the experimental results obtained during the wear testing procedure.     

Dry Sliding Wear Behaviour of Ti–6Al–4V Alloy Consisting of Bimodal Microstructure

In the present paper, dry sliding wear behaviour of Ti–6Al–4V titanium alloy consisting of bimodal microstructure sliding against EN-31 steel at different sliding velocities (0.3, 0.6 and 0.9 m/s) and applied loads (60, 80 and 100 N) has been studied using a multiple Tribo tester and the results are presented. Two wear mechanisms have been identified irrespective of the applied load: oxidative wear occurs at the lowest sliding velocities and delamination wear occurs at the highest. Results indicated that by increasing the sliding velocity a transition from oxidative wear to delamination wear occurs with a corresponding minimum in the loss of volume due to wear. These results have been described by the analysis of the wear debris and that of the worn specimens using XRD, optical microscopy, FESEM and interpreted based on the metallurgical characteristics of titanium alloys which influence the wear resistance.     

Effect of Tin on the Wear Properties of Spray Formed Al–17Si Alloy

In the present study, the effect of Sn on the dry sliding wear behavior of spray formed and hot pressed Al–17Si alloy as a function of applied load and sliding speed has been investigated and compared with that of as-cast alloy. The microstructure of spray formed Al–17Si alloy consists of fine and uniformly distributed Si particles and that of Al–17Si–10Sn alloy consists of fine and uniform dispersion of Si particles and ultra-fine Sn particles in α-Al matrix. Coarse and segregated microstructures were observed in as-cast alloys. The wear resistance of spray formed alloys is higher than that of as-cast alloys. The wear resistance of as-cast Al–17Si–10Sn alloy is higher than that of as-cast Al–17Si alloy. The high wear resistance of spray formed Al–17Si–10Sn alloy is discussed in the light of its microstructural features and the nature of worn-out surfaces.     

Mechanical Properties and Dry Sliding Wear Behaviour of Molybdenum Disulphide Reinforced Zinc–Aluminium Alloy Composites

ZA-27 alloy is a lightest alloy which offers excellent bearing and mechanical properties in automobile and industrial applications. In this study, the MoS₂ particles with 0.5, 1 and 1.5 (wt%) weight percentages were reinforced in ZA-27 alloy to form composites, which were fabricated by using ultrasonic assisted stir casting method. The ZA-27/MoS₂ composite specimens were examined for chemical composition with the aid of XRD technique and EDS. Microstructure analysis of the ZA-27/MoS₂ composites was studied using SEM. Tests were conducted for mechanical properties such as tensile strength and hardness on ZA-27/MoS₂ composites samples as per ASTM standards. Dry sliding wear behavior of the composites was tested at various operating conditions by using pin-on-disc apparatus. Microstructural images of the ZA-27 composites reveal that there is a uniform dispersion of the MoS₂ particles in the base material. From the results it is observed that the mechanical properties increases with ZA-27 reinforced with 0.5 wt% MoS₂ composite and further decreases with increase in the filler content. The enhanced wear resistance is observed in ZA-27 reinforced MoS₂ composites as compared to the unreinforced alloy. The wear rate of the ZA-27 composites decreases with the increase in filler content, further the worn surfaces as examined using SEM reveals the wear mechanism explaining the improved wear resistance of the particulate composites.     

Investigation on the Wear Properties of Primary Si Modified Al–20Si Alloy

In the present study, Al?C20Si alloy has been modified by Cu?C13P master alloy to obtain Al?C20Si?C0.1P alloy. The wear properties of Al?C20Si?C0.1P alloy have been investigated and compared with that of Al?C20Si alloy. The microstructure of Al?C20Si?C0.1P alloy consisted of primary and eutectic silicon distributed in the Al matrix. The size of primary Si is much smaller than that observed in Al?C20Si alloy. Wear tests have been conducted over a wide range of loads and sliding velocities. It has been observed that the wear rates of Al?C20Si?C0.1P alloy are lower than that of Al?C20Si alloy. The coefficient of friction is more or less constant in both the alloys but is low in Al?C20Si?C0.1P alloy. The better wear resistance of Al?C20Si?C0.1P alloy is discussed in the light of its modified microstructure evolved during solidification.     

Properties of CrossRolled Low Alloy White Cast Iron Grinding Ball

The lowenergy, multiimpact fracture resistance and the abrasiveness of the crossrolled low alloy white cast iron grinding balls were studied after heat treatments at residual rolling temperature. Moreover, the means by which they are damaged and characters of the wear surface were analyzed. The results show that high resistance to impact fracture and high abrasiveness can be achieved after appropriate heat treatment at residual rolling temperature. This kind of heat treatment technology has several advantages under low impact and hard abrasive. These results are very useful for determining the optimized heat treatment technology at residual rolling temperatures.     

Microstructure and Wear Performance of ECAP Processed Cast Al–Zn–Mg Alloys

In the present investigation, wear performance of equal channel angular pressing (ECAP) processed cast Al–Zn–Mg alloys under dry sliding wear conditions was studied against a steel disc. Initially, Al–Zn–Mg alloys (with 5, 10, 15% zinc and 2% magnesium) were ECAP processed. After ECAP, grain size was reduced and enhancement in the hardness was observed. Wear resistance of the alloys increased after ECAP processing. Wear resistance of the alloys also increased when the quantity of the zinc was increased in the alloys. But, wear resistance of all three alloys decreased with increase in the load and the sliding speed. Coefficient of friction of the alloys decreased after ECAP processing. Coefficient of friction of the alloys also decreased when the quantity of the zinc was increased in the alloys. Coefficient of friction of all three alloys increased with increase in the load and the sliding speed. Irrespective of the alloy composition and applied load, worn surfaces of the cast and homogenized samples were composed of plastic deformation, scratches and micro-ploughing. On the other hand, in ECAP processed samples, morphology of the worn surfaces depended on the applied load. Abrasive wear is the main wear mechanism perceived in cast and homogenized samples at all loads. While in ECAP processed samples, the wear mechanism shifted from adhesive and oxidation wear to abrasive wear with increase in the load. Formation of oxide layers on the surface of the sample increased with increase in the ECAP passes. In ECAP processed samples, transfer of iron content from the disc to the sample surface was identified.     

The Wear Behavior of In-Situ Al–AlN Metal Matrix Composites

Al–AlN composites are synthesized using NH₄Cl + CaO powder as a nitrogenation precursor in the melt of pure aluminum. In-situ formation of AlN to varying volume fraction is attempted using different proportion of NH₄Cl + CaO precursor into the aluminum melt held at 700 °C. Mechanical properties of synthesized metal matrix composites are evaluated for different volume fraction and distribution of AlN particles in aluminum matrix. Agglomeration of AlN is noticed with increasing precursor addition and synthesis time into the aluminum matrix. Due to heterogeneous distribution of AlN particles in aluminum matrix, marginal changes in hardness are observed. Pin on disc, dry sliding wear of metal matrix composites is carried to study wear behavior of synthesized composites. Composite with good dispersion of AlN particulates has shown higher hardness and wear resistance. Present paper discusses wear behavior of composites with different weight fraction of AlN tested under load and sliding distance as wear parameters. The shearing mechanism of agglomerate due to friction and its correlation with the wear loss is also highlighted in the present paper.     

Sliding Wear Behavior Solid Lubricant Based Ni–Al–Bronze Surface Composite Developed by Friction Stir Processing

In this study, a nickel aluminium bronze (NAB) metal matrix composite reinforced with solid lubricants i.e. graphite and molybdenum disulphide (MoS₂) was prepared by friction stir processing. Friction stir processing (FSP) refined the grain structure as compared to the as-cast NAB. The micrographs of graphite reinforced matrix revealed fine globular α phase with some elongated morphology α phases, whereas MoS₂ reinforced surface composite mainly exhibited fine α phase particles. FSP also resulted in the distribution of solid lubricant particles in the NAB matrix. The hardness of the composites decreased with the addition of the solid lubricants in NAB matrix. SEM–EDS analysis of the reinforced NAB matrix confirmed the presence of solid lubricants. The influence of solid lubricants on the sliding wear behavior of NAB metal matrix was investigated by using the design of experimental approach. The experimental results revealed better wear resistance of the NAB–MoS₂ surface composite as compared to graphite reinforced and FSPed NAB surface. SEM–EDS analysis of worn out surfaces and wear debris were carried out for understanding the wear mechanism.     

Experimental Investigation on Adhesive Wear Behavior of Al–Si6Cu/Ni Coated SiC Composite Under Unlubricated Condition

This paper studies the dry sliding wear behavior of Al–Si6Cu/Ni coated SiC metal matrix composite fabricated using stir casting technique. The SiC reinforcement particles coated with Ni by electroless coating were incorporated at 10-wt% into the metal matrix. The wear behavior was studied on unlubricated pin-on-disc tribometer based on design of experiments modelled using Response Surface Methodology for various sliding parameters such as applied load, sliding velocity and sliding distance. The minimum wear rate condition and optimum condition of the parameters were detected from the developed model. The analysis of variance showed the influence of each parameter on wear rate. The confirmation experiments were done to ensure the validity of the developed regression model. The worn-out surface morphologies of the metal composite were studied using scanning electron microscope analysis. From the experimental results it was found that the parameter which influenced the wear behavior was applied load followed by sliding velocity and distance. The confirmatory experiments confirmed the RSM’s design as precise statistical model in developing regression results with less error. The surface plot of wear characteristics showed that irrespective of the conditions of sliding velocity and distance the wear rate increased on increasing the load. The wear rate exhibited a non linear relationship with sliding velocity and distance. The scanning electron microscopy revealed that higher material deformation was observed at higher load resulting in severe wear of the composite material.     

Processing of Cu–Al–Ni Alloy by Spray Atomization and Deposition Process

The present work describes a new route for the preparation of Cu–Al–Ni alloy strips via spray atomization and deposition route. The route consists of atomizing liquid Cu–Al–Ni alloy with a jet of argon gas in a closed chamber, at a pressure of 1 MPa. The semi-solid Cu–Al–Ni droplets are subsequently collected on the steel substrate placed vertically below the liquid metal stream in the atomization chamber to form a three-dimensional preform. The deposit produced on the substrate contains ~?5% porosity. The microstructural details of the spray deposited Cu–Al–Ni strips explains particularly the presence of porosity, formation of splats during the flight of spray casting and the associated microstructural evolution in Cu–Al–Ni spray deposit are explained.     

Dry Sliding Wear Behaviors of Iron Addition to Nickel–Aluminum Bronze Produced by Mechanical Alloying

Transactions of the Indian Institute of Metals - In this study, different amounts of iron are added to nickel–aluminum bronze produced by mechanical alloying and its effects on...     

The Structure and Properties of Precipitation-Strengthened Composites Produced From a Cast Alloy in the Al–Si–Mg System

Powder Metallurgy and Metal Ceramics - The properties of precipitation-strengthened composites produced from an aluminum alloy were studied. The composites were prepared by powder and casting...     

Mechanical Properties and Corrosion–Abrasion Wear Behavior of Low-Alloy MnSiCrB Cast Steels Containing Cu

Two medium carbon low-alloy MnSiCrB cast steels containing different Cu contents (0.01 wt pct and 0.62 wt pct) were designed, and the effect of Cu on the mechanical properties and corrosion–abrasion wear behavior of the cast steels was studied. The results showed that the low-alloy MnSiCrB cast steels obtained excellent hardenability by a cheap alloying scheme. The microstructure of the MnSiCrB cast steels after water quenching from 1123 K (850 °C) consists of lath martensite and retained austenite. After tempering at 503 K (230 °C), carbides precipitated, and the hardness of the cast steels reached 51 to 52 HRC. The addition of Cu was detrimental to the ductility and impact toughness but was beneficial to the wear resistance in a corrosion–abrasion wear test. The MnSiCrB cast steel with Cu by the simple alloying scheme and heat treatment has the advantages of being high performance, low cost, and environmentally friendly. It is a potential, advanced wear-resistant cast steel for corrosion–abrasion wear conditions.     

Effect of Aging Time on Mechanical Properties and Wear Characteristics of Near Eutectic Al–Si–Cu–Mg–Ni Piston Alloy

Al–12Si–3Cu–1 Mg–1.78Ni alloy is widely used for piston parts in automobile industry. The present paper investigates the effect of aging time for 1–16 h at 180 °C after solution treatment of the alloy at 500 °C for 5 h, on alloys prepared by gravity casting and squeeze casting. The wear rate of the alloy shows a minimum at an intermediate aging time. The hardness and ultimate tensile strength showed a peak at intermediate aging time. Mechanical properties and wear resistance are found to be better in squeeze cast alloy. The result are explained based on the microstructure developed during casting process and on heat treatment for various durations.     

Commencement of Ordering in Al–0.69Mg–0.31Si Alloy

Transactions of the Indian Institute of Metals - Early stages of ordering in dilute Al–0.69(at.%)Mg–0.31(at.%)Si alloy, aged at 373 K for 120 h and 7200 h and...     

Studying the Influence of Rolling Deformation Degree and Pb Content on the Hardness of Spray Deposited Al–6Si Alloy Using Linear Regression Analysis

Powder Metallurgy and Metal Ceramics - In this study, Al–6Si alloys with various Pb content (0, 10, 20, and 30 wt.%) were prepared by the spray deposition technique. Gaussian or bell-shaped...