Carbide Particle-Reinforced Tungsten Composites in Extreme Hazard Environments

2013 ◽  
pp. 509-532
Author(s):  
Guiming Song ◽  
Yujin Wang ◽  
Yu Zhou
Keyword(s):  
Finite Element Method ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Early Stage ◽  
Peripheral Zone ◽  
Damage Mode ◽  
Ablation Resistance ◽  
Tic Particle ◽  
Shock Resistance ◽  
Disk Sample

The ablation as well as the associated thermal shock resistance of tungsten composites reinforced by TiC and ZrC particles is investigated with an oxyacetylene equipment. 30TiC/W (30TiC stands for 30 vol. % TiC particle content in tungsten, the same below) and 40TiC/W fail to withstand the thermal shock of 2000ºC/s during heating. In contrast, 30ZrC/W and 40ZrC/W withstand the thermal shock. Additionally, ZrC/W composites exhibit better ablation resistance than TiC/W composites. The thermal stress fields of the composite at both macro-/micro-scales induced by thermal shock at the early stage of the ablation are analyzed using finite element method. The calculated results of the damage mode of the composites show that crack initiates at the disk sample peripheral zone and then propagates to the sample center, which is consistent with the experimental observation.

scholarly journals Influence of Bond Coat on Thermal Shock Resistance and Thermal Ablation Resistance for Polymer Matrix Composites

2021 ◽  
Vol 8 ◽  
Author(s):  
Jiahui Zhou ◽  
Jianing Jiang ◽  
Longhui Deng ◽  
Jingqi Huang ◽  
Jieyan Yuan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Shock ◽  
Bonding Strength ◽  
Thermal Ablation ◽  
Thermal Shock Resistance ◽  
Polymer Matrix Composites ◽  
Coating System ◽  
Matrix Composites ◽  
Ablation Resistance ◽  
Shock Resistance

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.

Effects of Chromium Content on Thermal Shock Cycle Resistance of (TiCr)N Hard Reactive Films

2017 ◽  
Vol 737 ◽  
pp. 150-155
Author(s):  
Bu Shi Dai ◽  
Jun Zhang
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
High Speed ◽  
Early Stage ◽  
High Speed Steel ◽  
Deposition Process ◽  
Air Cooling ◽  
Cr Content ◽  
Oxidation Stage ◽  
Shock Resistance

The (TiCr)N hard reactive films with 4 different Ti/Cr atomic ratios are prepared by using multi-arc ion plating. The Ti and Cr targets are used as cathodes in the co-deposition process. The high speed steel (HSS) specimens are adopted as substrate. The thermal shock cycle tests in air cooling (AC) way for the (TiCr)N films are carried out. The test temperatures are chosen as 600 °C and 700 °C, respectively. The changes of the surface compositions and morphology in the thermal shock cycle tests are investigated. The effects of Cr content in the (TiCr)N films, the temperature at which the thermal shock cycle tests are performed and the cycling times on the thermal shock resistance of the (TiCr)N films are discussed and analyzed in detail. The thermal shock behaviors of the (TiCr)N films show that the thermal shock cycling process of the (TiCr)N films consists of two stages, the steady-state oxidation stage with the increase of oxygen content at the early stage of thermal cycles, and, the instable oxidation stage with the oxidation aggravation and the occurrence of the surface cracks. The simple increase of Cr content in the (TiCr)N film does not improve the thermal shock resistance of the (TiCr)N films but easy to aggravate the surface oxidation process during the thermal shock cycles.

Numerical Simulation of Thermal Shock Tests of Carbon-Containing Refractories

2012 ◽  
Vol 538-541 ◽  
pp. 660-664
Author(s):  
Hui Min Liu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Finite Element Method ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Heating Process ◽  
Stress Changes ◽  
Quenching Process ◽  
Shock Resistance ◽  
The Mathematical Model

To appraise the thermal shock resistance of carbon-containing refractories correctly, its thermal stress changes in thermal shock tests were analyzed by finite element method, and the mathematical model appraising its thermal shock fracture was built. The results show when the sample of carbon-containing refractory suffers thermal shock, the main damaged areas lie its centre during sharp heating process, but the sides during quenching process. The later is the main reason causing its damage. When appraising the thermal shock resistance of carbon-containing refractory by dip spalling method, the result matches fracture index.

Thermal shock resistance of Ti3SiC2 ceramic under extremely rapid thermal cycling

2021 ◽  
Vol 866 ◽  
pp. 158985
Author(s):  
Xiaojia Su ◽  
Yiwang Bao ◽  
Detian Wan ◽  
Haibin Zhang ◽  
Ludi Xu ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Shock Resistance ◽  
Rapid Thermal Cycling
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