Ablation Behavior Research Articles

Heterogeneous ablation behavior of SiCf/SiC composite by nanosecond pulse laser

Heterogeneous ablation behavior of SiCf/SiC composite by nanosecond pulse laser

Study on laser ablation characteristics of tree obstacles in transmission lines

IntroductionAs a new and efficient method for obstacle removal, laser clearance has promising applications in eliminating tree obstacles in transmission lines. This paper aims to explore various aspects related to the laser ablation of tree obstacles in transmission lines through simulation and experimentation.MethodsThis paper employs simulation and experimentation to test the ignition time, burn-through time, peak temperature, and basic carbonization rate of various types of tree obstacles in transmission lines. Additionally, it analyzes the effects of tree density, laser power, clearance distance, and tree moisture content on laser ablation characteristics.ResultsThe results reveal that different types of tree obstacles exhibit distinct ablation characteristics. With increasing tree density, both the ignition and burn-through times increase, while the peak temperature and basic carbonization rate decrease. Additionally, laser power and clearance distance significantly influence laser ablation behavior. Higher laser energy density results in greater heat flux density, leading to shorter ignition and burn-through times and higher peak temperatures and carbonization rates. Moreover, the tree obstacle with the highest moisture content (58.4%) had the shortest burn-through time of 46.56 s, whereas the one with the lowest moisture content (14.8%) took the longest at 58.41 s, which demonstrates that increased moisture content enhances the laser ablation rate.DiscussionThese findings provide a basis for the application of laser-based tree obstacle removal in power transmission lines. The understanding of how different factors such as tree density, laser power, clearance distance, and moisture content affect the laser ablation process can help in optimizing the laser clearance operations for more efficient removal of tree obstacles in transmission lines.

Study on the anti-ablation behavior of (Ti,W)3AlC2 under oxyacetylene flame above 2500 K

To evaluate the reliability of (Ti,W)3AlC2 in aerospace ablation conditions, the ablation behavior of (Ti,W)3AlC2 ceramic is investigated by using oxyacetylene flame above 2550 K. Results show a four-stage process exists with the formation of TiO2-Al2TiO5-Al2O3. Once the central ablation temperature exceeds 2350 K, the innermost Al2O3 layer melts and collapses, exposing the decomposed TiCx-Al matrix directly to the flame with rapid oxidation and a remarkable increase of the linear ablation rate. The melt finally flows out with the flame from the ablation center and solidifies into a stripe-like TiO2-Al2TiO5 eutectic oxide above the protective oxide layer. The refractory W particles detected in the eutectic TiO2-Al2TiO5 may retard the flowing rate of the fluid by increasing its viscosity, resulting in a better ablation resistance performance in the later period of the ablation process, making the linear ablation rate lower from 10.30 μm/s of Ti3AlC2 to 9.01 μm/s of (Ti,W)3AlC2.

Combinatorial approach to predict synergistic ablation behavior of carbon fiber phenolic composites under aerodynamic loading

The study conducts a comprehensive analysis across 1-D, 2-D, and 2-D axisymmetric geometries, investigating temperature profiles, surface recession patterns, pyrolysis gas flow dynamics, and density fluctuations within the composite material. The findings highlight the effectiveness of the FEA technique in modeling complex multi-physical interactions associated with ablation phenomena. The carbon-phenolic composites, characterized by low thermal conductivity, high specific heat capacity, and substantial char yield, are shown to be particularly well-suited as ablative materials. The char layer formed during ablation acts as an additional insulating barrier, enhancing thermal protection. In a specific case study, a 2 cm thick composite laminate was subjected to an intense heat flux of 200 W/cm2 for 180 s. The results demonstrate that the Thermal Protection System (TPS) effectively maintains the back face temperature below 350 K for the initial 60 s under uniform heat flux conditions. However, beyond this period, the back face temperature gradually increases, reaching 1698 K at the end of the 180-s simulation. These insights into the material’s thermal performance under severe heat exposure conditions provide valuable guidance for applications requiring effective heat management and thermal protection.

Microstructure and ablation behavior of C/C–HfC–SiC composites fabricated by reactive melt infiltration with Hf–Si alloy

AbstractC/C–HfC–SiC composites were prepared by reactive melt infiltration using Hf–Si alloy (Hf, more than 95 wt%) with a density of 3.86 g/cm3 and an open porosity of 8.34%. The microstructure, mechanical properties, and ablation behavior at high temperatures were studied in detail. SiC played a crucial role in alleviating the thermal mismatch between HfC and PyC, which formed at the interface between the carbon matrix and the HfC matrix. The flexural strength and modulus of C/C–HfC–SiC composites were 237 MPa and 37.6 GPa, respectively. The C/C–HfC–SiC composites exhibited excellent ablation resistance with a linear ablation rate of 8.9 × 10−3 mm/s and maintained a surface temperature above 2925°C during ablation. During this process, HfO₂ remained in a molten state with high viscosity and served as a thermal barrier, while the volatilization of SiO₂ effectively removed heat, protecting the composites from further ablation.

Ablation behavior of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-SiC-Si ceramics via reactive melt infiltration

(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-SiC ceramics with an open porosity of only 0.49 % were successfully fabricated in this work by the reactive melt infiltration (RMI) method. Air plasma flame ablation behavior of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-SiC ceramics under 2300 °C temperature exhibited excellent resistance with mass and linear ablation rates of 3.66 mg/s and 0.88 μm/s, respectively. During ablation, the transition from continuous melting sublimation of Si and oxidation of SiC to oxidation of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2 occurred. The uphill diffusion of Ti atoms transited (Ti,Zr,Hf,Nb,Ta)Ox to Ti(NbxTa1-x)2O7 while Zr0.5Hf0.5O2 continuously precipitated. A multicomponent oxide layer of (Ti,Zr,Hf,Nb,Ta)Ox along with (Zr,Hf)6Ta2O17, (Hf,Zr)(TiO4)2, and (Zr,Hf)x(Ti,Ta)1-xO embedded in SiO2 melt was eventually formed on the ceramic surface. This oxide layer was spread above the high melting point Zr0.5Hf0.5O2, Ti(NbxTa1-x)2O, and low oxygen content (Ti,Zr,Hf,Nb,Ta)Ox to form a stable, dense, and high viscosity protective layer.

Effect of non-static pre-oxidation treatment on the cyclic ablation behavior of SiC-ZrC/SiC multilayer coated graphite

SiC-ZrC based ceramics have caught much attention as coatings for graphite materials. However, the coefficient of thermal expansion (CTE) mismatch between coatings and matrix severely limits their application in harsh environments. Herein, we proposed a non-static pre-oxidation treatment under an air pressure of 0.05 MPa to increase the surface roughness of graphite matrix to 18.054 μm and then prepared the SiC-ZrC/SiC multilayer coating on the pre-oxidized graphite. The results demonstrate that a firm interlocking structure was formed between SiC-ZrC/SiC multilayer coating and graphite matrix, which effectively improved the bonding strength and enhanced the cyclic ablation resistance of coatings. The bonding strength of SiC-ZrC/SiC multilayer coated on graphite pre-oxidized under negative pressure was 5.70±0.42 MPa, which was 54.89% higher than that on graphite pre-oxidized under atmospheric pressure (3.68±0.08 MPa). After the plasma ablation for 360 s (60 s × 6), the linear and mass ablation rates of SiC-ZrC/SiC multilayer coated graphite which was pre-oxidized under negative pressure were -0.083 μm/s and 0.101 mg/s, respectively.

Transient behavior of ablation and swelling for C/C composite and HfC-coated C/C composite in an arc-heated wind tunnel

This study investigated and modeled the transient behavior of surface recession, defined as the difference between ablative length and swelling length, for thermal protection materials within a high-enthalpy flow. Needle punch carbon-carbon (NPCC) and hafnium carbide coated carbon-carbon (HfC-coated NPCC) were exposed to high-enthalpy flow with a heat flux of 7.67 MW/m2 generated by an arc-heated facility. The NPCC and the HfC-coated NPCC represent an ablative surface and a non-ablative surface, respectively. Surface recession histories were estimated through an image analysis and visualizations monitored by a high-speed camera. Moreover, measured data including surface temperature histories, mass loss, and total length were presented. We proposed the models for the transient recession on the ablative surface and the non-ablative surface considering the ablation and the swelling. The ablative length was calculated using non-dimensional parameter B′, which computes ablation rates under equilibrium air conditions. While B’ modeling accurately predicted the ablation rates, it could not reflect the swelling phenomenon during an initial heating phase. The swelling was modeled with consideration of the thermal expansion. Specifically, the effect of increased porosity near the ablative surface was incorporated into the thermal expansion coefficient. The model developed in this study well agreed with the experimental data.

Femtosecond laser-induced damage threshold incubation in SrTiO3 thin films

This study delved into the microfabrication process on SrTiO3 thin films using femtosecond laser pulses, focusing on characterizing ablation behavior and elucidating on incubation parameters. A combination of microscopy techniques and systematic analysis of laser-material interactions provided insights into the features and fundamental processes governing the laser-induced modification of SrTiO3 thin films. The cutting profile morphology indicated high-resolution material removal, with line widths ranging from 0.6 to 1.6 µm, depending on number of pulses and energy. The study revealed a low incubation parameter for SrTiO3 thin films, quantified as (0.03 ± 0.01), indicating that a considerable number of pulses is required to cause damage to the material. Additionally, threshold energies for damage were determined to be 17.9 nJ for 20,000 pulses and 35.2 nJ for a single pulse. AFM analysis showed that the depth of the micromachined lines increased from approximately 80 nm to 315 nm with higher pulse energies, confirming substantial material removal. The Keldysh parameter provides insights into ionization mechanisms under femtosecond-laser irradiation, highlighting the dominance of tunneling ionization. Using higher pulse energies, the center of the microstructures exhibited significantly reduced Raman signals, correlating with substantial material removal, which was confirmed by atomic force microscopy. EDS analyses indicated that the elemental composition of the irradiated regions closely resembled the stoichiometric composition of SrTiO3, while the center of the microstructures showed significant oxygen levels but lacked titanium and strontium, consistent with the findings from AFM and Raman microscopy.

Improving the ablation performance of largely deformed silicone rubber-based composites under coupled mechanical-thermal-oxidative conditions by implementing deformable carbon fiber fabrics

Silicone rubber-based composites are used as thermal protection materials due to their large deformability and excellent thermal insulation properties. In this study, two types of commercially available silicone rubbers were selected as the matrices for preparing flexible thermal protection materials. The influence of applied strain rates on the microstructure, ablation and ceramifiable behavior of silicone rubbers was studied. The research showed that the ablation performance of silicone rubbers deteriorated greatly at large strain rates. The reinforcement using deformable carbon fiber fabrics was proposed to effectively counter the deterioration of the ablative properties incurred by applying external strain. The back-face temperature reached as low as 186 °C when the samples were ablated at above 1000 °C for 50s at a strain rate of 20 %. The proposed strategy was proved helpful in developing high performance flexible thermal protection systems that exhibit promising application in the fields of aerospace and fire protection among others.

Ablation resistance of C/C–Hf1-xZrxC composites under an oxyacetylene flame at above 2700 °C

To the better application of C/C composites in thermal components of vehicles above 2700 °C, C/C–Hf1-xZrxC composites were prepared by CLVD, and the ablation behavior of composites was investigated. The results show that C/C–Hf0.5Zr0.5C has excellent ablation properties with linear and mass ablation rates of −0.23 μm/s and −0.31 mg/(s·cm2), respectively. ZrO2 molten phase and HfxZr1-xO2 particles are generated on the surface of C/C–Hf1-xZrxC composites during ablation. During the ablation process, defects are healed by the ZrO2 molten phase due to its mobility, which inhibits the diffusion of oxygen into the substrate. The ZrO2 molten phase is stabilized by the pinning effect of the HfxZr1-xO2 particles, which makes the ZrO2 molten phase better resistant to the scouring of the air stream. A relatively complete oxide layer is generated on the C/C–Hf0.5Zr0.5C surface, with a moderate amount of HfxZr1-xO2 exerting a pinning effect to hold the ZrO2 molten phase.

Ablation behavior of Cf/ZrC–SiC ultra–high temperature ceramic composites in oxyacetylene torch and plasma wind tunnel

Ablation performance of Cf/ZrC–SiC composites was evaluated in both oxyacetylene torch and plasma wind tunnel and further comparative study was conducted on the ablation behavior under two environments. An oxyacetylene torch test led to a pitting corrosion of Cf/ZrC–SiC composites and their ablated surface was covered by a porous zirconia layer. The Cf/ZrC–SiC nose tip endured the plasma wind tunnel test rather well with only 0.43 % height loss after total 1050 s exposure due to the formation of a compact zirconia scale. This compact zirconia scale kept its consolidation to the composite body and acted as the ablation-resistant and thermal shielding layer of the nose tip.

Ceramic Matrix Composite Cyclic Ablation Behavior under Oxyacetylene Torch.

To study the ablation properties and differences of plain-woven SiC/SiC composites under single and cyclic ablation. The ablation test of plain-woven SiC/SiC composites was conducted under an oxyacetylene torch. The results indicate that the mass ablation rate of cyclic ablation is lower than that of single ablation, whereas the line ablation rate is higher. Macro-microstructural characterization revealed the presence of white oxide formed by silica on the surface of the ablation center region. The fibers in the central region of the ablation were ablated layer by layer, and the broken fiber bundles exhibited a spiky morphology with numerous silica particles attached. The oxide layer on the surface and the silica particles on the fibers, which are in the molten state formed in the high-temperature ablation environment, contribute to resisting ablation. Thermal shock during cyclic ablation also played a role in the ablation process. The thermal shock causes cracks in the fiber bundles and matrix of the SiC/SiC composites. This study helps to apply SiC/SiC composite to complex thermal shock environments.

The ablation behavior of diamond/Cu composites by infrared nanosecond pulsed laser

This paper investigates the material removal behavior of diamond/Cu composites by multi-passes infrared nanosecond pulsed laser ablation, focusing on the formed surface cracks, periodic ripples, profile evolution and deposition. Combining nanosecond laser ablation experiments with simulations based on thermophysical properties is then undertaken to effectively reduce the maximum thermal stress and inhibit crack initiation and propagation. Three types of cracks were identified in nanosecond laser ablation, which were influenced by the diverse thermophysical properties of the material and the temperature gradient. The periodic ripples of 300–1800 nm on the sidewalls of the machined groove on diamond grains were induced when the laser fluence approached the ablation threshold, which did not even appear on the copper matrix as the thermal effects dominate. The groove profile showed a limited change as the ablation passes further increase to be over 40 due to the plasma shielding effect inside the groove, the laser defocusing phenomenon and the increased difficulty of sputtering the molten material. In addition, the different ablation mechanisms of diamond and copper resulted in the formation of overlapping deposition layers with changed surface characteristics at varying laser energy densities. The uneven island-like recast layer affected the uniformity of the ablated grooves, which was dependent on the material microstructure and accumulated laser energy.

Ablation behaviour and mechanism of in-situ NbC composite coating under plasma jet

NbC composite coatings of Nb2O5-Al-SiC system (in-situ) and NbC-SiC-Al2O3 system (ex-situ) were successfully prepared on graphite substrate by plasma spraying, respectively. The ablation resistance of two systems of NbC composite coatings was evaluated by plasma jet, and the ablation mechanism of the Nb2O5-Al-SiC system coating prepared in-situ was revealed. The results showed that the NbC-SiC-Al2O3 system composite coating has completely failed after ablation for 10 s, and the Nb2O5-Al-SiC system coating only has a small amount of spalling at the edge of the coating surface after ablation for 20 s. The excellent ablation resistance of Nb2O5-Al-SiC system coating was attributed to the formation of a Nb2O5 liquid-phase film on the surface of the coating during the ablation process, which can effectively block the penetration of heat and oxygen into the coating. Moreover, the reaction between Nb2O5 and Al2O3 at high temperatures generated the high-temperature stable phase AlNbO4, which can further improve the structural stability of the Nb2O5 film, and then improve the ablation resistance of the Nb2O5-Al-SiC system coatings.

Revealing the ablative behavior and mechanism of a 2D C/SiC Ti3SiC2 modified composite through a multi-scale laser ablation model

Ti3SiC2 MAX phase ceramic has effectively enhanced the oxidation resistance of C/SiC composites. However, there is still a need for a numerical ablation model that can analyze the ablative behavior of 2D C/SiC composites. To address this, an efficient, phenomenological multi-scale ablation model, including the thermal property theoretical model, oxidation, decomposition, and sublimation ablation models, is established for revealing the effect of Ti3SiC2 on the ablation resistance of the 2D C/SiC composite. The ablative behavior is evaluated using the continuous-wave laser with different laser power densities as the heat source and used as a basis for numerical model verification. The results show that the Ti3SiC2 MAX phase ceramic can improve the ablation resistance of the 2D C/SiC composite under different laser power densities. The ablation roughness is reconstructed through the mesoscopic geometry structure and maximum/minimum ablation depth. The numerical model can analyze the effect of the mesoscopic geometry structure parameters on the ablation behavior. The model can provide a predicting method for the quantitative ablative calculation of 2D C/SiC and matrix-modified composites.

Ablation behaviour and mechanical performance of ZrB2-ZrC-SiC modified carbon/carbon composites prepared by vacuum infiltration combined with reactive melt infiltration

Ablation behaviour and mechanical performance of ZrB2-ZrC-SiC modified carbon/carbon composites prepared by vacuum infiltration combined with reactive melt infiltration

Improved oxidation and ablation resistance of SiCf/SiC-HfB2 composites: Role of oxygen-blocking scale and protection mechanism

To improve the oxidation and ablation resistance of SiCf/SiC composites, the as-synthesized ultrafine HfB2 powder was used as the modification phase to fabricate SiCf/SiC-HfB2 composites, and their oxidation and ablation behaviors were investigated. Compared with the unmodified SiCf/SiC composites, the oxidation resistance at 800–1500 °C and the ultra-high temperature ablation resistance of SiCf/SiC-HfB2 composites were significantly improved. After oxidation, a compact compound glass scale consisting of HfO2, HfSiO4 and Si-Hf-O glass was formed, providing the effective oxidation protection. A dual-phase oxide scale composed of HfO2 skeleton and Si-Hf-O glass was formed after ablation, exhibiting the high viscosity, the significant oxygen-blocking effect and resistance to gas flow scouring. The improved oxidation and ablation resistance of SiCf/SiC-HfB2 composites could be attributed to the effective protective role of oxygen-blocking scales formed during the oxidation and ablation processes.

Microstructure and ablation behavior of Zr-based ultra-high-temperature gradient composites

To obtain high-performance Zr-based ultra-high-temperature composites, Zr-based ultra-high-temperature gradient composites were prepared by changing the laying method of the infiltrant via reactive melt infiltration. The effects of different infiltrant laying methods on the microstructure and ablative properties of Zr-based ultrahigh-temperature gradient composites were investigated. The results showed that the gradient structure of the Zr-based ultrahigh-temperature gradient composites differed when the composition ratio of the infiltrant was changed. When the thicknesses of the Zr/Mo/Si layers were 6/4/12 mm and 8/2/12 mm, the SiMoZrC solid solution content in the samples increased and decreased along the infiltration direction, respectively. The gradient samples were ablated in an oxyacetylene flame at 3000 °C for 40 s. The ablation resistance of the sample was the highest when the infiltrant was a powder and the thickness of the Zr/Mo/Si layer was 6/4/12 mm.

Ablation behavior and high temperature ceramization mechanism of TiB2-B4C-ZrC modified carbon fiber/boron phenolic resin composites

The carbon fiber (CF) reinforced boron phenolic resin (BPR) matrix composite, renowned for its exceptional ablation resistance, represents a promising material for high-temperature applications. However, hypersonic vehicles are subjected to increasingly challenging service environments, which necessitate materials capable of enduring even more extreme temperatures. Consequently, there is a growing need for composites that exhibit superior ablation resistance. To tackle these demanding requirements, this research initiative introduces the integration of ceramizable fillers, including TiB2, B4C, and ZrC, into the composite structure to create a high-temperature ceramizable system. The experimental findings indicate that the composites formulated with this innovative system demonstrate extraordinary ablation resistance, even when exposed to oxyacetylene flames with a heat flux of 4364 kW/m2. Notably, the measured linear ablation rate and mass ablation rate were recorded at −0.012 mm/s and 0.0268 g/s, respectively. These values are exceptionally low. Subsequent analysis utilizing X-ray diffraction (XRD) and additional characterization techniques has confirmed the formation of a dense ceramic layer with a B-C-O-Ti-Zr composition on the composite surface at elevated temperatures. This ceramic layer acts as a formidable barrier, significantly mitigating the ablation effects caused by high-temperature exposure. Meanwhile, it is pertinent to note that the formation of the ceramic layer is accompanied by an endothermic reaction, which consequently leads to a reduction in the thermal conduction of the composite to some extent.