Wear Rate Of Alloy Research Articles

Microstructure and tribological performance of Co-B intermetallic compounds under water environment

Cobalt-boride (Co-B) alloys, as promising wear resistant materials, can form different intermetallic compounds. In this work, supercooling treatment is applied to control the microstructures and compounds in the alloys, and the related mechanical and tribological properties have been investigated systematically. The results suggest that besides FCC-Co and HCP-Co, it forms Co3B and minor Co2B in the as-cast samples, Co3B, Co2B and Co23B6 under different supercooling degree. Tribological experiments of these alloys under distilled water environment demonstrate that the Co-B alloy containing Co23B6 has the best tribological performance, followed by Co2B and Co3B. The coefficient of friction and wear rate of alloy containing Co23B6 are about 0.2 and 1.6 × 10−6 mm3/Nm, respectively, which are reduced by 60 % and one magnitude lower compared to the as-cast sample containing Co2B and Co3B. The promising tribological result of Co23B6 is attributed to the formation of tribolayer, which is rich in Co(OH)2, silicate, SiO2 and possibly H3BO3. This work provides guideline for tuning phases of Co-B alloys when using as rubbing parts in moisture environment.

A Comparative Study of Microstructure, Coefficient of Friction and Wear Rate of Alloy Ni-Cr-B-Si-C-W

The present work aims at the study of the dry disc pion contact and the complex phenomenon of the wear as well as the sliding friction of our sample elaborated by a hot isotactic compression and the pion. This study consists in determining the coefficient of friction and the influence of the tribological parameters on this phenomenon as well as determining the loss of mass and the wear rate of study sample. In order to enhance the assurance of the validity of the results of tribological study of Ni-Cr-B-Si-C-W alloy in laboratories and compare that to the tribological conditions in reality and industries. This work presents the results of the new approach to compares the wear behavior of the sample between a theoretical study (tribometer)and another in service (a test bench) that reproduces approximately the same conditions as the tribometer (normal load, sliding speed and distance traveled) by measuring the loss of mass and wear rate.

Studies on Dry Sliding Wear Characteristics of Cermet WC-Co Particulate Reinforced Al7075 Metal Matrix Composite

Abstract In the present work, an attempt is made to synthesize cermet (WC-Co) reinforced Al7075 metal matrix composite by liquid metallurgy route. The dry sliding wear behavior of these prepared composites was studied with varying sliding speed, load and sliding distance. Cermet in an amount of 6 wt% is used as reinforcement in Al7075 matrix. Microstructural characterization of the prepared composites is carried out using SEM/EDX and XRD studies. X-ray diffraction studies have revealed the peaks corresponding to α-Al, WC, Co and minor Al5W phases. SEM/EDX characterization revealed the uniform distribution of cermets in Al matrix. Dry sliding wear characteristics of the prepared composites were studied using a pin-on-disc testing machine. The wear rate for alloy and composites decreased with increase in sliding speed and increased with increase in applied load and increasing sliding displacement. The worn surfaces of the composites were investigated using optical microscope.

Tribological and corrosion behaviors of Mg56.5Cu27Ag5Dy11.5 bulk metallic glass in NaCl solution

In this study, the tribological behaviors of Mg56.5Cu27Ag5Dy11.5 bulk metallic glass (BMG) in air and NaCl solution were investigated using ball-on-disk reciprocating friction. The Mg56.5Cu27Ag5Dy11.5 BMG exhibits higher strength and hardness than those of commercial AZ31B alloy and pure Mg. The wear rate of the Mg56.5Cu27Ag5Dy11.5 in air is 3.8×10−7mm3·mm−1·N−1, which is superior to those of AZ31B alloy (7.3×10−7mm3·mm−1·N−1) and pure Mg (6.5×10−7mm3·mm−1·N−1). The wear mechanism of Mg56.5Cu27Ag5Dy11.5, AZ31B, and pure Mg sliding in air is dominated by oxidation and abrasive wear. The wear rates of alloys in NaCl decrease in the following order: 8.3×10−7mm3·mm−1·N−1 for pure Mg, 6.3×10−7mm3·mm−1·N−1 for AZ31B, and 5.4×10−7mm3·mm−1·N−1 for Mg56.5Cu27Ag5Dy11.5. The Mg56.5Cu27Ag5Dy11.5 and pure Mg demonstrate inferior corrosion resistance in NaCl to that of AZ31B. Thus, the Mg56.5Cu27Ag5Dy11.5 and pure Mg subject to tribocorrosion controlled by synergistic effects of abrasive and corrosive wear, which results in a large wear rate during sliding in NaCl. The possible mechanism of corrosion accelerating wear deterioration is discussed, which provides the guidance for the improvement in the tribocorrosion resistance of Mg-based BMGs for further load-bearing applications.

Effect of Aluminum Content on Wear Resistance of Hot-Forged Multiphase Steel

A medium-carbon steel was alloyed with Mn, Cr, Si, and Al to obtain carbide-free bainite steel. The thermomechanics and chemistry of steel were used to produce medium carbon containing four phases: ferrite, pearlite, bainite, and chromium carbide. The morphologies of different phases were characterized and analyzed by using optical and scanning electron microscopes. An abrasive dry sliding wear (pin on ring) of two types of medium-carbon, hot-forged steels containing different aluminum contents was investigated at different pressures and sliding velocities. The sliding duration time was 30 minutes under dry sliding conditions. The wear rate of Alloy 1 and 2 revealed negligible wear rates at low velocity and pressure. On the other hand, the wear rate highly increased to maximum at maximum velocity and pressure for Alloy 1 and 2. Alloy steel 2 of 2 pct Al revealed a maximum wear rate of 720 mg/min compared with 160.8 mg/min for Alloy 1 contains 1 pct Al. Experimental results showed that increased aluminum content is directly proportional to the ferrite volume fraction, which greatly influences the wear resistance performance and mechanical properties of the two types of steel.

Friction and wear behavior of nanoeutectic Fe1.87C0.13 under air and vacuum conditions

In this paper, the tribological behavior of nanoeutectic Fe1.87C0.13 alloy and its coarse-grained-eutectic counterpart under air and vacuum was investigated. The results showed that the wear rate of both alloys was lower in air than in vacuum, and their friction coefficient was related to applied load and testing atmosphere. The nanoeutectic Fe1.87C0.13 alloy exhibited lower wear rate than the coarse grained counterpart in both environments. The wear rate of both alloys increased but the friction coefficient decreased with increasing applied load under both air and vacuum. The dominant wear mechanisms were adhesion wear in vacuum but oxidation wear along with slight delamination in air.

Dry Sliding Wear Behavior of Mg-Zn-Gd Alloy before and after Cryogenic Treatment

The dry sliding wear behavior of Mg-1.5Zn-0.15Gd alloy before and after cryogenic treatment was studied by wear tests using a ball-on-disk configuration at room temperature. The wear tests were performed at speeds ranging from 0.05 to 0.7 m/s under three different applied loads (5, 7, and 10 N). The worn surfaces and wear debris were analyzed using a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS). The results show that the wear rate of alloy decreases with increasing sliding speed. Two different wear mechanisms were identified under different sliding speeds. During low-speed sliding at 0.05 m/s, abrasive wear occurs with a high wear rate. When the sliding speed increases to 0.5 m/s, the wear mechanism transforms into oxidative wear with a low friction coefficient and wear rate. The wear resistance of the alloy is improved after cryogenic treatment. Such improvement is minor at high sliding speeds due to the formation of an oxidation layer on the wear surfaces, which weakens the hard-phase support effect during wearing. A wear map of each mechanism as a function of load and sliding speed is provided.

Degradation of Titanium Drillpipe From Corrosion and Wear

Summary Drilling deeper than 35, 000 ft is limited by the extreme hook loads of steel drillpipe and temperature constraints of aluminum drillpipe. Titanium Alloys Ti-6A1-4V and Beta C have been proposed for use in drillpipe for wells deeper than 35, 000 ft because of their high strength/weight ratios, superior high-temperature corrosion resistance, and thermal stability. Their suitability in drilling environments, however, has not been evaluated. To determine the corrosion and wear characteristics of two types of titanium-alloy drillpipe under dogleg conditions, a test cell was constructed to test titanium drillpipe joints in contact with API Spec. 5CT Grade P-110 casing in different drilling muds. Titanium-alloy pipe and Grade P-110 casing wear rates were measured, and tests showed that both titanium-alloy pipes exhibited much greater wear than did steel drillpipe in water-based mud under the same conditions. Test data showed that the total wear rate of Alloys Ti-6A1-4V and Beta C in a drilling environment is a combination of mechanical wear and corrosion.