Influence of Graphite on Tribological Properties of Hexagonal Boron Nitride Hybrid/Polyimide Composites in Wide Temperature Range

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Yanming Wang ◽  
Peng Cai ◽  
Tingmei Wang ◽  
Qihua Wang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Boron Nitride ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Transfer Film ◽  
Antiwear Property ◽  
Wear Rates ◽  
Higher Temperature ◽  
Polyimide Composites

Tribological and mechanical properties of aramid fiber (AF), graphite (Gr), and hexagonal boron nitride (h-BN) hybrid polyimide composites were investigated under room and high temperature. Results show that, Gr in composite reinforced with AF and h-BN can reduce coefficient of friction (COF) and improve antiwear property of composites under room temperature. Gr can accelerate the formation of transfer film under high temperature without sacrificing the wear resistant of composites. Transfer film of composites reinforced with Gr and h-BN simultaneously present more smooth and uniform compared with that of composites reinforced with only AF and h-BN. However, under higher temperature, composite reinforced with pure Gr present higher COFs and wear rates (WRs) compared with composites filled with h-BN and Gr simultaneously. Comprehensively, composite filled with 10% AF, 3% h-BN, and 4% Gr is the optimum composition.

Room temperature spin valve effect in the NiFe/Gr–hBN/Co magnetic tunnel junction

2016 ◽  
Vol 4 (37) ◽  
pp. 8711-8715 ◽  
Author(s):  
Muhammad Zahir Iqbal ◽  
Salma Siddique ◽  
Ghulam Hussain ◽  
Muhammad Waqas Iqbal
Keyword(s):  
Boron Nitride ◽  
Tunnel Junction ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Spin Valve ◽  
Magnetic Tunnel Junction ◽  
Valve Effect ◽  
First Time

Graphene and hexagonal boron nitride (hBN) have shown fascinating features in spintronics due to their metallic and tunneling behaviors, respectively. In this work, we report for the first time room temperature spin valve effect in NiFe/Gr–hBN/Co configuration.

Cubic Boron Nitride as a New Semiconductor for Optoelectronics: Luminescence Properties and Potentialities

1989 ◽  
Vol 162 ◽  
Author(s):  
Koh Era ◽  
Osamu Mishima
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Room Temperature ◽  
Cubic Boron Nitride ◽  
Visible Region ◽  
Vibrational Structure ◽  
Luminescence Properties ◽  
Optoelectronic Applications ◽  
P Type

ABSTRACTIn cubic boron nitride made by high pressure and high temperature technique in our institute, we have found three luminescence bands in the ultraviolet and the short visible region at room temperature by cathode-ray excitation. They are: a band having vibrational structure and ascribable to undoped state of the crystal, a band ascribable to p-type doping and a band ascribable to n-type doping. Discussion is made on differences between the injection luminescence and the cathodoluminescence. Potentialities and difficulties in realizing the potentialities of cBN for optoelectronic applications are discussed.

scholarly journals Comparison of Mechanical and Microstructural Properties of as-Cast Al-Cu-Mg-Ag Alloys: Room Temperature vs. High Temperature

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1330
Author(s):  
Muhammad Farzik Ijaz ◽  
Mahmoud S. Soliman ◽  
Ahmed S. Alasmari ◽  
Adel T. Abbas ◽  
Faraz Hussain Hashmi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Mechanical Testing ◽  
Tensile Testing ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Microstructural Properties ◽  
Testing Environments ◽  
Mechanical And Microstructural Properties ◽  
Mg Content

Unfolding the structure–property linkages between the mechanical performance and microstructural characteristics could be an attractive pathway to develop new single- and polycrystalline Al-based alloys to achieve ambitious high strength and fuel economy goals. A lot of polycrystalline as-cast Al-Cu-Mg-Ag alloy systems fabricated by conventional casting techniques have been reported to date. However, no one has reported a comparison of mechanical and microstructural properties that simultaneously incorporates the effects of both alloy chemistry and mechanical testing environments for the as-cast Al-Cu-Mg-Ag alloy systems. This preliminary prospective paper presents the examined experimental results of two alloys (denoted Alloy 1 and Alloy 2), with constant Cu content of ~3 wt.%, Cu/Mg ratios of 12.60 and 6.30, and a constant Ag of 0.65 wt.%, and correlates the synergistic comparison of mechanical properties at room and elevated temperatures. According to experimental results, the effect of the precipitation state and the mechanical properties showed strong dependence on the composition and testing environments for peak-aged, heat-treated specimens. In the room-temperature mechanical testing scenario, the higher Cu/Mg ratio alloy with Mg content of 0.23 wt.% (Alloy 1) possessed higher ultimate tensile strength when compared to the low Cu/Mg ratio with Mg content of 0.47 wt.% (Alloy 2). From phase constitution analysis, it is inferred that the increase in strength for Alloy 1 under room-temperature tensile testing is mainly ascribable to the small grain size and fine and uniform distribution of θ precipitates, which provided a barrier to slip by deaccelerating the dislocation movement in the room-temperature environment. Meanwhile, Alloy 2 showed significantly less degradation of mechanical strength under high-temperature tensile testing. Indeed, in most cases, low Cu/Mg ratios had a strong influence on the copious precipitation of thermally stable omega phase, which is known to be a major strengthening phase at elevated temperatures in the Al-Cu-Mg-Ag alloying system. Consequently, it is rationally suggested that in the high-temperature testing scenario, the improvement in mechanical and/or thermal stability in the case of the Alloy 2 specimen was mainly due to its compositional design.

Manufacturing and High Temperature Mechanical Properties of Inconel 713C by Using Metal Injection Molding

2012 ◽  
Vol 602-604 ◽  
pp. 627-630 ◽  
Author(s):  
Kyu Sik Kim ◽  
Kee Ahn Lee ◽  
Jong Ha Kim ◽  
Si Woo Park ◽  
Kyu Sang Cho
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Injection Molding ◽  
Room Temperature ◽  
Tensile Tests ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
High Temperature Mechanical Properties ◽  
Inconel 713C

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.

Influences of Solution Temperatures on Microstructure and Mechanical Properties of near α Titanium Alloy

2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
High Temperature ◽  
Room Temperature ◽  
Solution Temperature ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Β Phase ◽  
Α Phase ◽  
New Type

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.

Tribological and Corrosion Behavior of HVOF Sprayed Cr3C2-NiCr with Nickel Cladded Graphite and Hexagonal Boron Nitride

2021 ◽  
Author(s):  
M. Oechsner ◽  
T. Engler ◽  
H. Scheerer ◽  
Y. Joung ◽  
K. Bobzin ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Friction And Wear ◽  
Room Temperature ◽  
Solid Lubricant ◽  
Hexagonal Boron Nitride ◽  
Solid Lubricants ◽  
Wear Behaviour ◽  
Wear Volume ◽  
Coating Microstructure ◽  
Sprayed Coatings

Abstract High-velocity oxyfuel (HVOF) sprayed coatings of Cr3C2-NiCr containing solid lubricants such as nickel cladded graphite and hexagonal boron nitride were successfully developed and characterised with the aim of optimizing their friction and wear behaviour. HVOF technology was used for the integration of solid lubricants to achieve strong cohesion between particles while minimizing thermal decomposition. Coating microstructure and composition were measured and correlated to the results of tribological and corrosion tests. The integration of the solid lubricant greatly reduced friction and wear volume at room temperature, but the lubricating effect was highly dependent on atmosphere and temperature. Cr3C2-NiCr with hBN, however, tends to exhibit more stable wear resistance over a wider temperature range and can be used at temperatures beyond 450 °C.

Effect of Hot Processing on Mircrostructure and Properties of Flat Billets of TA15 Titanium Alloy

2021 ◽  
Vol 1016 ◽  
pp. 906-910
Author(s):  
Xin Hua Min ◽  
Cheng Jin
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
High Temperature ◽  
Room Temperature ◽  
High Strength ◽  
Slow Cooling ◽  
Microstructure And Mechanical Properties ◽  
Ta15 Titanium Alloy ◽  
The Ideal

In this paper,effect of the different forging processes on the microstructure and mechanical properties of the flat flat billets of TA15 titanium alloy was investigated.The flat billiets of 80 mm×150 mm×L sizes of TA15 titanium alloy are produced by four different forging processes.Then the different microstrure and properties of the flat billiets were obtained by heat treatment of 800 °C~850 °C×1 h~4h.The results show that, adopting the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling, the primary αphases content is just 10%, and there are lots of thin aciculate phases on the base. This microstructure has both high strength at room temperature and high temperature, while the properties between the cross and lengthwise directions are just the same. So the hot processing of the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling is choosed as the ideal processing for production of aircraft frame parts.

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