Effect of Chromium on Microstructure and Oxidation Wear Behavior of High-Boron High-Speed Steel at Elevated Temperatures

In order to investigate the effect of Cr content on the microstructures and oxidation wear properties of high-boron high-speed steel (HBHSS), so as to explore oxidation wear resistant materials (e.g., hot rollers), a scanning electron microscope, an X-ray diffractometer, an electron probe X-ray microanalysis and an oxidation wear test at elevated temperatures were employed to investigate worn surfaces and worn layers. The results showed that the addition of Cr resulted in the transformation of martensite into ferrite and pearlite, while the size of the grid morphology of borides in HBHSSs was refined. After oxidation wear, oxide scales were formed and the high-temperature oxidation wear resistance of HBHSSs was gradually improved with increased additions of Cr. Meanwhile, an interaction between temperature and load in HBHSSs during oxidation wear occurred, and the temperature had more influence on the oxidation wear properties of HBHSSs. SEM observations indicated that a uniform and compact oxide film of HBHSSs in the worn surface at elevated temperatures was generated on the worn surface, and the addition of Cr also reduced the thickness of oxides and inhibited the spallation of worn layers, which was attributed to improvements in microhardness and oxidation resistance of the matrix in HBHSSs. A synergistic effect of temperature and load in HBHSSs with various Cr additions may dominate the oxidation wear process and the formation and spallation of oxide films.

Fretting wear behavior of micro-arc oxidation coating fabricated on AZ91magnesium alloy

In this study, the effect mechanisms between the fretting wear behavior and properties of micro-arc oxidation (MAO) coatings fabricated by different anodic voltages (AVs) on AZ91 magnesium alloy were investigated. The microstructure and macroscopic mechanical properties of the MAO coatings were analyzed by various characterization means. The evolution rule of fretting wear behaviors was carried out through sliding fretting wear experiment under different test parameters. The results showed that the increased in AV increased the MAO coating surface roughness and elastic modulus. The fretting wear resistance of magnesium alloy also enhanced after treatment by MAO, and the improvement effect was positively correlated to AV. Further studies revealed that the wear mechanisms of AZ91 magnesium alloy were oxidation wear and fatigue spalling, and that of MAO coating was mixed abrasive wear and fatigue spalling.

Investigation of the Wear Behavior of AA6082 Against Different Counterparts

In this study, the effect of different counterparts on the wear resistance of AA6082 aluminum alloy was investigated. In tests using pin-on-disk method, 6 mm diameter Al2O3, 100Cr6 and WC-6Co balls were used as counterparts. The tests were carried out using 500 m sliding distance and 5N load. The lowest specific wear rate was measured as 7.58x10-4 mm3/Nm in WC-6Co / AA6082 couple, and the highest value was measured as 9.71x10-4 mm3/Nm in 100Cr6/AA6082 couple. In the Al2O3/AA6082 couple, the specific wear rate of the AA6082-T6 sample was determined as 8.23x10-4 mm3/Nm.While it was observed that the dominant wear type in the 100Cr6/AA6082 pair was abrasive wear, oxidation wear and oxide tribofilm were detected in the WC-6Co/AA6082 and Al2O3/AA6082 couple besides the abrasive wear.

Effect of VN and TiB2-TiCx Reinforcement on Wear Behavior of Al 7075-Based Composites

Al 7075 alloy, 15 wt.% VN/7075 composites, and 20 wt.% TiB2-TiCx/7075 composites were prepared by ball milling with subsequent hot-pressing sintering. The microstructure, hardness, and wear properties at room temperature to 200 °C of Al 7075-based composites with different reinforcement phases were discussed. The grain uniformity degree values of 15 wt.% VN/7075 composites and 20 wt.% TiB2-TiCx/7075 composites were 0.25 and 0.13, respectively. The reinforcement phase was uniformly distributed in 15 wt.% VN/7075 composites and 20 wt.% TiB2-TiCx/7075 composites, almost no agglomeration occurred. The order of hardness was 20 wt.% TiB2-TiCx/7075 composites (270.2 HV) > 15 wt.% VN/7075 composites (119.5 HV) > Al 7075 (81.8 HV). At the same temperature, the friction coefficient of 15 wt.% VN/7075 composites was the lowest, while the volume wear rate of 20 wt.% TiB2-TiCx/7075 composites was the lowest. With the increase of temperature, the wear mechanism of Al 7075 changed from spalling wear to oxidation wear and adhesion wear. However, the wear mechanisms of 15 wt.% VN/7075 and 20 wt.% TiB2-TiCx/7075 composites changed from abrasive wear at room temperature to wear mechanism (oxidation wear, abrasive wear, and adhesive wear) at medium and low temperature. Comprehensive wear test results indicated that 20 wt.% TiB2-TiCx/7075 composites had excellent tribological properties at medium and low temperature.

Effect of heat treatment and electric discharge alloying on the tribological performance of Selective Laser Melted AlSi10Mg

Selective Laser Melting (SLM) is an emerging additive manufacturing technology for fabrication of complex light-weight components along with improved mechanical properties. The present work investigates influence of various post processing methods such as Heat Treatment and Electric Discharge Alloying (EDA) on ambient and elevated temperature wear behavior of Selective Laser Melted (SLM) AlSi10Mg alloy and compared with its tribological behavior with cast AlSi10Mg. The dry wear tests were conducted using a Pin On Disk (POD) tribometer with EN-31 as counter body. The EDA treated SLM AlSi10Mg showed the least wear rate and coefficient of friction (COF) at both ambient and elevated temperatures (1.05 × 10−4 mm31/Nm and 0.434 & 3.12 × 10−5 mm3/Nm and 0.531 respectively) due to its higher hardness (189.8 HV) as compared to other samples. The wear rate and COF of cast specimen are found to be highest among all specimens at both ambient and elevated temperatures (1.34 × 10−4 mm3/Nm and 0.528 and 4.49 × 10−5 mm3/Nm and 0.724 respectively). Lower wear rate and higher COF are observed at elevated temperature due to the excessive formation of wear-resistant oxides (Al2O3, SiO2 and MgO) and glaze layers for all samples compared to ambient temperature wear behaviors of its counter parts. Abrasive wear, adhesive wear, oxidation wear and surface delamination are the prominent wear mechanisms observed for ambient and elevated temperatures for all the specimens.

Effects of Titanium-Implanted Dose on the Tribological Properties of 316L Stainless Steel

The effects of titanium (Ti) ion-implanted doses on the chemical composition, surface roughness, mechanical properties, as well as tribological properties of 316L austenitic stainless steel are investigated in this paper. The Ti ion implantations were carried out at an energy of 40 kV and at 2 mA for different doses of 3.0 × 1016, 1.0 × 1017, 1.0 × 1018, and 1.7 × 1018 ions/cm2. The results showed that a new phase (Cr2Ti) was detected, and the concentrations of Ti and C increased obviously when the dose exceeded 1.0 × 1017 ions/cm2. The surface roughness can be significantly reduced after Ti ion implantation. The nano-hardness increased from 3.44 to 5.21 GPa at a Ti ion-implanted dose increase up to 1.0 × 1018 ions/cm2. The friction coefficient decreased from 0.78 for un-implanted samples to 0.68 for a sample at the dose of 1.7 × 1018 ions/cm2. The wear rate was slightly improved when the sample implanted Ti ion at a dose of 1.0 × 1018 ions/cm2. Adhesive wear and oxidation wear are the main wear mechanisms, and a slightly abrasive wear is observed during sliding. Oxidation wear was improved significantly as the implantation dose increased.

Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

Effect of shot peening on the wear behavior of Ti(C,N) coating on TA15 alloy prepared by double glow plasma carbonitriding

Purpose The purpose of this paper is to prepare Ti(C,N) coatings on TA15 treated and not treated by shot peening using double glow plasma alloying technique. The effect of shot peening on the wear behavior of Ti(C,N) coatings is discussed. Design/methodology/approach The Ti(C,N) coatings were prepared by double glow plasma alloying technique on two different TA15 substrate; one is shot peened and the other is not. Findings Ti(C,N) coating on SP-treated TA15 was thicker and denser, and the grain size was smaller compared with that on original TA15. Compared with the Ti(C,N) coating on original TA15, the wear resistance of that on SP-treated TA15 is improved. Ti(C,N) coating on SP-treated TA15 showed higher nanohardness and bearing capacity than that on original TA15. Originality/value For double glow plasma alloying technique, surface quality, surface activity and other factors will have influence on the thickness and density of the coating. The wear mechanisms of Ti(C,N) coating on original TA15 are serious abrasive wear and oxidation wear. However, the wear mechanism of Ti(C,N) coating on SP-treated TA15 is slightly oxidation wear. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0283/

Research on surface properties of Ti-6Al-4V alloy by multi-ultrasonic rolling

The main purpose of this paper was to investigate the effect of the multiple ultrasonic surface rolling process (USRP) on the surface mechanical properties and wear mechanism of Ti-6Al-4V. Firstly, X-ray diffraction (XRD) microscopic analysis, work hardening and residual stress were used to measure and characterize the surface performance by USRP. The friction coefficient and wear morphology were obtained by the scanning electron microscope (SEM), three-dimension (3D) white light interferometer and energy dispersive spectrometer (EDS). The results showed that the material surface mechanical properties was effectively improved by the USRP, and the surface grains were refined to form nanoscale. It also can be found that the wear resistance of the material surface was effected by the surface mechanical properties. With the increase of processing, the main wear mechanism changed from delamination-based oxidation wear to adhesive wear with the increase of processing.

Effects of plasma surface Ta alloying on the tribology behavior of γ-TiAl

To improve the wear resistance of ?-TiAl alloy, Ta alloy layer was prepared on surface by double glow plasma surface alloying technique. The tribology behavior of Ta alloy layer against Si3N4 at 25?, 350? and 500? were comparatively studied. The results showed that Ta alloy layer comprised a deposition layer and a diffusion layer. The deposition layer played a role in protection as a soft film. With the increase of temperature, the wear mechanism of ?-TiAl changed from abrasive wear to coexistence of abrasive wear and oxidation wear. Ta alloy layer?s wear mechanism changed from adhesive wear to coexistence of adhesive wear and oxidation wear. Surface Ta alloying process significantly reduced the wear volume, the specific wear rate and the friction coefficient of ?-TiAl and improved the wear resistance properties of ?-TiAl.