Modification of Tribolayers of a Titanium Alloy Sliding against a Steel

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Y. Zhou ◽  
W. Jiang ◽  
W. Chen ◽  
X. L. Ji ◽  
Y. X. Jin ◽  
...  

The nonprotective tribolayers of the titanium alloy were modified into additives-containing tribolayers through an artificial addition of multilayer graphene (MLG), Fe2O3 nanomaterials, or their mixtures with various proportions on the titanium alloy/steel sliding interface. The sustainability of the modified tribolayers under a high load was evaluated by the critical sliding distance for a mild-to-severe wear transition. The modified tribolayers were found to significantly improve or deteriorate tribological performance of the titanium alloy, which was decided by their ingredients. The pure MLG- or Fe2O3-containing tribolayers, because of their lacking load-bearing or lubricant capacity, presented poor sustainability and readily lost protection to cause high wear loss or frictional coefficient. However, for the addition of various mixtures of MLG and Fe2O3, the modified tribolayers possessed a double-layer structure consisting of friction-reducing MLG- and wear-resistant Fe2O3-predominated layers. They presented a sustainable protection, thus remarkably improving the tribological performance of the titanium alloy.

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 116 ◽  
Author(s):  
Ping Liu ◽  
Yongwei Zhu ◽  
Qi Shen ◽  
Meifu Jin ◽  
Gaoyan Zhong ◽  
...  

This paper presents the influence of an inorganic Al2O3 layer over MoS2 particles on the tribological performance of electroless Ni–P–MoS2/Al2O3 composite coatings fabricated without using surfactants. The Al2O3-coated MoS2 particles were prepared by a heterogeneous nucleation process. The dry sliding tests of the composite coatings were tested against a WC ball. SEM was used to observe the surface morphology of particles, composite coatings, and worn surfaces. The results indicate that the coverage of an Al2O3 coating on MoS2 particles significantly affects the surface morphology, frictional coefficient and wear loss of the composite coatings. The incorporation of Al2O3-coated MoS2 particles with lower coverage (up to 7% of Al2O3) could obtain compact surface structure of composite coatings, which contribute to reduced wear loss. However, higher coverage would lead to loose surface structure of the composite coatings, and thus increase their wear loss.


2018 ◽  
Vol 385 ◽  
pp. 407-412
Author(s):  
Gui Qiang Guo ◽  
Dong Sheng Li ◽  
Xiao Qiang Li ◽  
Xuan Zhao Huang

Superplastic forming/diffusion bonding (SPF/DB) process is widely used in aviation titanium alloy parts forming. PAM-STAMP was utilized to simulate the SPF/DB process of a Ti-6Al-4V double layer structure part in rear fuselage at 920°C and reach the thickness distribution of the part. Then the part was formed based on simulation. The thickness distribution of the practical part was measured and compared with the simulation result. The results show that the thickness distributions of practical and simulated part fit well with each other.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2237
Author(s):  
Eder H. C. Ferreira ◽  
Angela Aparecida Vieira ◽  
Lúcia Vieira ◽  
Guilhermino J. M. Fechine

Here, nanocomposites of high-molecular-weight polyethylene (HMWPE) and HMWPE-UHMWPE (80/20 wt.%) containing a low amount of multilayer graphene oxide (mGO) (≤0.1 wt.%) were produced via twin-screw extrusion to produce materials with a higher tribological performance than UHMWPE. Due to the high viscosity of both polymers, the nanocomposites presented a significant concentration of agglomerates. However, the mechanical (tensile) and tribological (volumetric loss) performances of the nanocomposites were superior to those of UHMWPE. The morphology of the nanocomposites was investigated using differential scanning calorimetry (DSC), microtomography, and transmission electron microscopy (TEM). The explanation for these results is based on the superlubricity phenomenon of mGO agglomerates. It was also shown that the well-exfoliated mGO also contained in the nanocomposite was of fundamental importance as a mechanical reinforcement for the polymer. Even with a high concentration of agglomerates, the nanocomposites displayed tribological properties superior to UHMWPE’s (wear resistance up to 27% higher and friction coefficient up to 57% lower). Therefore, this manuscript brings a new exception to the rule, showing that agglomerates can act in a beneficial way to the mechanical properties of polymers, as long as the superlubricity phenomenon is present in the agglomerates contained in the polymer.


Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 56
Author(s):  
Ashutosh Sharma ◽  
Byungmin Ahn

Metallic and alloyed coatings are used widely in several decorative and technology-based applications. In this work, we selected Sn coatings plated on Cu substrates for joining applications. We employed two different plating baths for the fabrication of Sn and Ni coatings: acidic stannous sulfate for Sn and Watts bath for Ni layer. The plating current densities were varied from 100–500 mA/cm2. Further, the wear and friction behavior of the coatings were studied using a ball-on-disc apparatus under dry sliding conditions. The impact of current density was studied on the morphology, wear, and coefficient of friction (COF) of the resultant coatings. The wear experiments were done at various loads from 2–10 N. The sliding distance was fixed to 7 m. The wear loss was quantified in terms of the volume of the track geometry (width and depth of the tracks). The results indicate that current density has an important role in tailoring the composition and morphology of coatings, which affects the wear properties. At higher loads (8–10 N), Sn coatings on Ni/Cu had higher volume loss with a stable COF due to a mixed adhesive and oxidative type of wear mechanism.


2017 ◽  
Vol 867 ◽  
pp. 19-28 ◽  
Author(s):  
J. Lakshmipathy ◽  
Subburaj Rajesh Kannan ◽  
K. Manisekar ◽  
S. Vinoth Kumar

In this article, an attempt was made to study the mechanical behaviour of AA7068 - 6 vol. % of MoS2 - X vol. % of WC (X = 0, 5, 10 and 15) hybrid aluminium composites produced by blend–press–sinter methodology. Compacted Powders (700MPa) were sintered at different temperatures (450 0c, 500 0c and 550 0c ) in order to find the influence of sintering temperature on mechanical properties and tribological behavior of AA7068 hybrid composites.The sintered samples have been characterized by x-ray diffraction (XRD) method for identification of phases and also to investigate the phase changes. The change in density, hardness and porosity values of composites were reported. The composite with 15 vol. % of tungsten carbide and 6 vol. % of MoS2 showed the highest hardness and density at the sintering temperature range of 550 0c. Pin-on-disc type apparatus was used for determining the wear loss occurring at different conditions. The hybridization of the two reinforcements enhanced the wear resistance of the composites, especially under high applied load, sliding distance and sliding speeds. Due to this, the hybrid aluminium composites can be considered as an outstanding material where high strength and wear-resistant components are of major importance, predominantly in the aerospace and automotive engineering sectors. The morphology of the wear debris and the worn out surfaces were analyzed to understand the wear mechanisms.


2022 ◽  
Vol 572 ◽  
pp. 151392
Author(s):  
Yufu Xu ◽  
Yichen Bao ◽  
Zhichao Liu ◽  
Quan Zheng ◽  
Yinhui Dong ◽  
...  

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