AN INFLUENCE OF SELECTED MECHANICAL PARAMETERS OF MMC ON THE THERMAL SHOCK RESISTANCE

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5807-5812
Author(s):  
DARIUSZ RUDNIK ◽  
ZBIGNIEW KOWALEWSKI ◽  
KRYSTYNA PIETRZAK ◽  
ANDRZEJ WOJCIECHOWSKI

The results concerning the basic mechanical properties are presented for selected metal matrix composites (MMC). Three types of composites were produced by means of squeeze casting and next heat treatment. An influence of reinforcement type on the crack appearance in matrix and composite material was analyzed. Theoretical evaluation of the thermal shock resistance was proposed on the basis of conventional mechanical characteristics. Moreover, the qualitative metallographic investigations were carried out using optical microscopy method. A good consistence between the theoretical evaluation of thermal shock resistance and experimental data was achieved.

2017 ◽  
Vol 889 ◽  
pp. 30-35 ◽  
Author(s):  
Erie Martides ◽  
Budi Prawara ◽  
Husaini Ardy ◽  
Endro Junianto ◽  
Budi Priyono

Deposition of NiCr-CrC(20NiCr) metal matrix composite (MMCs) coating have been applied on the substrate of boiler tubes material with High Velocity Oxygen Fuel (HVOF) thermal spray method and constant parameter. Variation of particle size and composition on MMCs was conducted to determined the optimum conditions for boiler applications. Microvickers hardness, metallography and thermal shock resistance testing were investigated. The best performance for boiler tubes application is MMC NiCr-CrC(20NiCr) with 270 mesh of NiCr particles size and 60:40 of composition as evidence by the highest of hardness value (410 Hv) and slightly of discoloration after thermal shock resistance with two variation cooling medium. While at MMC NiCr-CrC(20NiCr) with 70:30 variation composition, coating hardness value will decrease in line with the smaller of particle size of NiCr.


1974 ◽  
Vol 6 (6) ◽  
pp. 732-736 ◽  
Author(s):  
A. G. Gashchenko ◽  
G. A. Gogotsi ◽  
A. G. Karaulov ◽  
I. N. Rudak

2018 ◽  
Vol 101 (10) ◽  
pp. 4743-4752 ◽  
Author(s):  
Xin Zhong ◽  
Yaran Niu ◽  
Hong Li ◽  
Haijun Zhou ◽  
Shaoming Dong ◽  
...  

2017 ◽  
Vol 23 (5) ◽  
pp. 672-678 ◽  
Author(s):  
Valentin ANTONOVIČ ◽  
Jerzy WITEK ◽  
Romualdas MAČIULAITIS ◽  
Renata BORIS ◽  
Rimvydas STONYS

This work investigates medium cement refractory castable with additives of carbon and polypropylene fibers. The peculiarities of microstructure changes in the fiber and castable matrix contact zone, channel formation, and changes of cold crushing strength of fiber additives, which have a refractory castable matrix under temperature treatment, were investigated. The investigation results allowed to predict that using a mix of fibers more effective than using them indi­vidually. The influence of fiber additives on the mechanical characteristics and thermal shock resistance of the refractory castable with fiber additives was tested. It was found that the addition of carbon fiber has a positive impact on the ther­mal shock resistance of the investigated castable, which is confirmed by the results obtained by thermal cycling, as well as by the values calculated for thermal shock resistance R4 and Rst. In addition, the results of the investigation of thermal cycling show that the value of the thermal shock resistance was highest when a mixed fiber additive (CF+PP) was used.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jiahui Zhou ◽  
Jianing Jiang ◽  
Longhui Deng ◽  
Jingqi Huang ◽  
Jieyan Yuan ◽  
...  

Polymer matrix composites (PMCs) have been widely used in aero industry because of its low density and high strength-to-weight ratio. However, the application of PMCs is still limited by poor abrasion resistance, weak oxidation resistance and low operation temperature. In this study, Cu (Al)/NiCrAlY/YSZ triple layer coating system was deposited on glass fiber reinforced polyimide matrix composites (FPM) by means of High Velocity Oxygen Fuel (HVOF) for metallic coatings and Atmospheric Plasma Spraying (APS) for YSZ coating. The influences of different bond coats and different thickness of the top coat on the thermal shock resistance and thermal ablation resistance of the coating system was investigated. Compared with Al particle, Cu particle has a high density and correspondingly a high kinetic energy during spraying by HVOF, resulting in a high bonding strength between the Cu coating and FPM substrate. In the thermal shock test, the coating Cu/NiCrAlY/YSZ has a much longer lifetime than the coating Al/NiCrAlY/YSZ. After high-speed impact on the substrate, there is a great compressive stress at the interface, which makes a plastic deformation to the substrate, and the particles are closely embedded into the substrate to form a strong mechanical interlock. The coating system consisting of 50 μm Cu, 50 μm NiCrAlY, and 200 μm 8YSZ exhibited the best thermal shock resistance, thermal ablation resistance and bonding strength. The increase of the top coat thickness will lead to the increase of residual stress and the decrease of bonding strength. The failure mechanism of the coating is mainly attributed to the residual stress in the deposition process and the thermal stress caused by thermal expansion mismatch.


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