Thermal Coefficient Of Resistance Research Articles

Fractional derivative modelling for consolidation of multilayered saturated soils with interfacial thermal contact resistance subjected to time-dependent heating and loading

In this paper, the one-dimensional rheological consolidation characteristics of multilayered saturated soil foundations under time-dependent loading and heating are investigated by considering the semi-permeability and the interface thermal resistance. By introducing the fractional derivative model and the thermos-elastic theory, a thermo-mechanical coupling model is established to describe the rheological properties of saturated soils. Semi-analytical solutions for strain, temperature increment, pore water pressure and settlement were derived through the Laplace transform and its inverse. The accuracy of the solutions proposed in this paper has been verified by comparing with existing solutions. The effects of different thermal contact models of the interface on the rheological properties of saturated soils under semi-permeable boundary are discussed, and the effects of fractional derivative order, constitutive material parameters, and thermal conductivity of soil on the thermal consolidation process are investigated. The results show that: neglecting the thermal resistance effect can result in an overestimates of the impact of rheological properties on the thermal consolidation process of saturated soils under semi-permeable boundaries; As the thermal resistance coefficient increases, the influence of soil thermal conductivity on settlement decreases.

Near infrared detection based on sputter-deposited Mn-Co-Ni-O films with a MSM structure

This work explores high-quality infrared detectors based on Mn-Co-Ni-O (MCNO) films, which were deposited by radio frequency magnetron sputtering at different temperatures ranging from 200 to 600 °C. Increasing the growth temperature was beneficial for forming smoother surfaces, higher crystallinity, and higher concentrations of Mn3+ and Mn4+ ions. However, it also resulted in a decrease in the thermal activation energy and temperature coefficient of resistance (TCR). MCNO-based metal–semiconductor-metal (MSM) structured detectors are highly sensitive to 885 nm infrared light, with the detector grown at 200 °C exhibiting the greater on/off ratio of 13.15, the largest responsivity of 0.23 A/W@-15 V, and the highest specific detectivity of 3.74 × 108 Jones and a rapid response/recovery time of 31.2/20.4 ms. This was attributed to due to its largest TCR value of −6.42 %/K, nano-pyrometric cone crystal grains on the surface, the largest Ov concentration, the lowest activation energy of Ov and electron-hole recombination efficiency, relatively high concentrations of Mn3+ and Mn4+ ions and lower resistance at 293 K. This research demonstrated that optimizing growth temperature is an effective method for significantly improving the properties of MCNO-based MSM structured detectors.

Investigation of B4C for inhibiting crystallization in silica at high temperatures

Amorphous silica has numerous high temperature applications due to its inherent thermal shock resistance and low coefficient of thermal expansion (CTE). However, at the high temperatures required for processing (>1200 °C), the metastable β-cristobalite phase preferentially forms and is accompanied by a volume change, and potential cracking, upon conversion to the low temperature α-cristobalite phase. The CTE of the final crystalline phase is an order of magnitude higher than its amorphous counterpart. Here experimental results demonstrate that small additions of B4C (3.5 wt%) effectively inhibit silica crystallization in powder and sintered gel-cast forms up to 22 h at temperatures as high as 1500 °C as confirmed via x-ray diffraction. The oxidation of B4C to B2O3 and its subsequent melt and evaporation disrupts the nucleation and growth of the cristobalite phase. The mechanism for crystallization inhibition is further explored through optical microscopy to probe changes in surface morphology.

Study on heat transfer performance of cold plate with grid channel

The utilization of cold plate radiators as a prevalent method for indirect liquid cooling has been extensively investigated and implemented in server cooling systems. However, there is a lack of comprehensive study on the application of this technology at the chip size, indicating a need for more development and exploration in this area. A proposal was made for a grid-channel chip cold plate heat sink to facilitate the dissipation of heat from a chip. tests were conducted to investigate the impact of the flow rate of the cold plate and the layout of the inlet and outlet on various thermal parameters, including the average temperature, maximum temperature, thermal resistance, and uniformity coefficient of the cold plate. The tests were specifically conducted under a chip power of 150W, and the accuracy of the simulation was confirmed through the use of FLUENT. The findings indicate that the cold plate effectively regulates the temperature of the chip, ensuring it remains below 85 °C throughout all experimental groups. In contrast to the single in single out configuration, the single-in multiple-out layout exhibits a higher degree of temperature uniformity within the cold plate. Nevertheless, it is important to note that augmenting the quantity of exits does not guarantee an improvement in heat transfer efficiency. This outcome is contingent upon the presence of a longitudinal flow channel shared by the outlet and intake, as well as the dispersion characteristics of the outlet. Enhancing the dispersion of the exit can significantly enhance the thermal transfer efficiency of the cold plate. Furthermore, a strategy for adjusting the aperture of the orifice is proposed as a solution to address the challenges related to flow uniformity and the issue of high pressure drop in the cold plate.

Development and evaluation of CrAlAgN self-lubricating coatings for high temperature metal forming dies

Conventional lubricants are widely used for die release as well as for cooling assistance on the die surface. However, lubrication is difficult at high temperatures. Oxidation and scaling occur on the work pieces that lead to poor surface finish and a possible warping of the material during cooling. The aim of this research is to develop self-lubricating CrAlAgN nanocomposite coatings for metal forming dies and evaluate their thermal fatigue resistance and wear behavior at elevated temperatures. The CrAlAgN coatings with different Ag contents have been deposited by plasma-enhanced magnetron sputtering. The structure and properties of the coatings were systematically studied to determine the optimal Ag content for achieving a combination of good adhesion, thermal fatigue resistance, and surface lubricity at elevated temperatures. The thermal fatigue resistance of the coatings was evaluated using thermal cyclic testing by cycling the coatings from room temperature to 800 °C up to 1200 cycles. The high temperature wear behavior of the coatings was evaluated using a tribometer up to 900 °C. Good thermal fatigue resistance and low coefficient of friction (COF) were observed in the CrAlAgN coatings with an Ag content in the range of 5–10 at. % at 800 °C. The CrAlAgN coating with 10 at. % Ag exhibited the lowest average COF of 0.05 at 800 °C. The COF of thick CrAlAgN coatings (8 at. % Ag) decreased from 0.5 to 0.2 from 500 to 900 °C, accompanied by an increase in the wear rate under more aggressive wear test conditions. The lubricity of the CrAlAgN coatings at high temperatures was attributed to the lubrication effects from the mixed oxides and encapsulated Ag diffused toward the surface. To further evaluate the coating performance, a hydraulic hot forging punch was coated with a thick CrAlAgN (8 at. % Ag) coating and evaluated in the industrial forging process. The preliminary in-plant trials demonstrated that the coating significantly reduced the dimensional distortion and wear for the forging punch.

A comprehensive study of Al-Cu-Mg system reinforced with nano-ZrO2 particles synthesized by powder metallurgy technique

More focus has recently been placed on enhancing the strength, elastic modulus, coefficient of thermal expansion (CTE), wear and corrosion resistance, and other qualities of aluminum (Al) alloys by varying the quantity of ceramics added for a range of industrial uses. In this regard, Al-4.2-Cu-1.6Mg matrix nanocomposites reinforced with nano-ZrO2 particles have been created using the powder metallurgy approach. The microstructure and particle size distributions of the produced powders were analyzed using a diffraction particle size analyzer, XRD, TEM, and SEM. To achieve good sinterability, the powders were compacted and sintered in argon. The sintered nanocomposites' mechanical, elastic, and physicochemical characteristics were measured. Additionally, the behavior of corrosion, wear, and thermal expansion were examined. The results showed a decrease in the particle sizes of the Al-Cu-Mg alloy by adding ZrO2 nanoparticles up to 45.8 nm for the composite containing 16 wt.% ZrO2. By increasing the sintering temperature to 570 °C, the densification of nanocomposites was enhanced. Also, the coefficient of thermal expansion and wear rate remarkably decreased by about 28 and 37.5% by adding 16 wt.% ZrO2. Moreover, microhardness yield, strength, and Young’s modulus were enhanced to 161, 145, and 64%, respectively, after adding 16 wt.% ZrO2. In addition, increasing the exposure time was responsible for decreasing the corrosion rate for the same sample.

A Delicate Balance Between Spin-Wave Mediated Weak Localization and Electron-Phonon Scattering in the Design of Zero Temperature Coefficient of Resistivity.

Zero thermal coefficients of resistivity (ZTCR) materials exhibit minimal changes in resistance with temperature variations, making them essential in modern advanced technologies. The current ZTCR materials, which are based on the resistivity saturation effect of heavy metals, tend to function at elevated temperatures because the mean free path approaches the lower limit of the semiclassical Boltzmann theory when the temperature is sufficiently high. ZTCR materials working at low-temperatures are difficult to achieve due to electron-phonon scattering, which results in increased resistivity according to Bloch's theory. In this work, the ZTCR behavior at low-temperatures is realized in pre-microstrained Mn3 NiN. The delicate balance between the resistivity contribution from electron-phonon scattering and spin-wave mediated weak localization is well revealed. A remarkable temperature coefficient of resistivity (TCR) value as low as 1.9ppmK-1 (50K≤T≤200K) is obtained, which is significantly superior to the threshold value of ZTCR behavior and the application standard of commercial ZTCR materials. The demonstration provides a unique paradigm in the design of ZTCR materials through the contraction effects of two opposite conductance mechanisms with positive and negative thermal coefficients of resistivity.

Experimental investigation of forced convection heat transfer for different models of PPFHS heatsinks with different fin-pin spacing

Cooling of electronic components is one of the most important concerns of manufacturers. Using heatsinks with different models is one of the recommended methods for cooling. To compare 12 types of heatsinks, including 3 types of fin-pin heatsinks with rectangular pins, 3 types of fin-pin heatsinks with circular pins, 3 types of fin-pin heatsinks with conical pins, and 3 types of simple fin heatsinks in 5, 7, and 9 fin types regarding forced displacement heat transfer, an experiment was conducted. A special setup designed and built for these types of heatsinks was used to conduct the test. The setup had dimensions of 100 cm × 12 cm x 3 cm with an opening of 120 cm × 120 cm for placing a fan to create airflow with variable speeds and a place for placing the heatsink at the end of the wind tunnel under variable temperatures. The test results showed that the maximum error in the two experimental tests was 6 %. Also, the results showed that in all 4 types of heatsinks, 7-fin pin types had 4 to 20% lower thermal resistance and 20 to 100% higher convection heat transfer coefficient compared to the 5- and 9-fin pin types respectively. When comparing the heatsinks with the same number of fins, it was observed that the 7 and 9-fin types of heatsinks with conical fins have lower thermal resistance and higher convection heat transfer coefficient than other types of heatsinks with the same number of fins, The conical fins having more than 81 % convection heat transfer coefficient compared to the plate fin heatsink. It was also observed that in the 5-pin fin heatsink design, the plate-fin heat sink had the lowest amount of heat resistance due to its higher surface area with the flowing air current.

Eco-friendly alkali lignin-assisted water-based graphene oxide ink and its application as a resistive temperature sensor

Inkjet-printable ink formulated with graphene oxide (GO) offers several advantages, including aqueous dispersion, low cost, and environmentally friendly production. However, water-based GO ink encounters challenges such as high surface tension, low wetting properties, and reduced ink stability over prolonged storage time. Alkali lignin, a natural surfactant, is promising in improving GO ink’s stability, wettability, and printing characteristics. The concentration of surfactant additives is a key factor in fine-tuning GO ink’s stability and printing properties. The current study aims to explore the detailed effects of alkali lignin concentration and optimize the overall properties of graphene oxide (GO) ink for drop-on-demand thermal inkjet printing. A meander-shaped temperature sensor electrode was printed using the optimized GO ink to demonstrate its practical applicability for commercial purposes. The sensing properties are evaluated using a simple experimental setup across a range of temperatures. The findings demonstrate a significant increase in zeta potential by 25% and maximum absorption by 84.3%, indicating enhanced stability during prolonged storage with an optimized alkali lignin concentration compared to the pure GO dispersions. The temperature sensor exhibits a remarkable thermal coefficient of resistance of 1.21 within the temperature range of 25 °C–52 °C, indicative of excellent sensitivity, response, and recovery time. These results highlight the potential of alkali lignin as a natural surfactant for improving the performance and applicability of inkjet-printable GO inks in various technological applications.

Optimization of microclimate parameters in sports frame and tent facilities

The paper considers measures to optimize energy costs in the heating of frame and tent facilities designed for sports events. Data on the available heating systems of temporarily used tent facilities are presented. It is shown that climatic conditions for athletes and the audience in these facilities do not meet the existing standards in the vast majority of cases. The combination of two factors affecting the microclimate parameters, i.e., the usage frequency and the low thermal resistance coefficient of the enclosing structures, requires the application of new practices not only in the form of climate control equipment operation mode, but also in the form of new monitoring techniques. The paper presents the results of a study of microclimate parameters in a frame and tent facility when using new techniques and approaches to climate control systems and to the process of forming climatic conditions depending on the clothing and the type of work performed. The results show that the introduction of new control algorithms and the implementation of new ways of monitoring microclimate parameters can save up to 30% of thermal energy while providing favorable microclimate parameters throughout the entire room, with the room reaching steady-state heating mode more than twice as fast. For the development of physical education and sports, it is necessary to use structures that can be quickly assembled and put into operation. For these purposes, frame and tent facilities are the best option.

A numerical study on high-velocity impact behaviour of ceramic composite laminates

Currently, silicon carbide (SiC) is of enormous concern because of its high compressive strength,high thermal conductivity, high thermal shock resistance and small coefficient of thermal expansion. SiC has its applicability in armored vehicles, hypersonic armaments, and bullet-resistant armours in the future. The current focus is on understanding the behavior of SiC as used in laminated ceramic armours during the ballistic impact for its profound use in armoured vehicles. To achieve these objectives, computational simulations have been performed for the aforementioned materials using ANSYS/AUTODYN. It was concluded that when SiC was used as a front layer in laminated armours, it significantly increased the strength of the material against the hitting projectiles. The aforementioned composite material was even successful against the sniper gun projectile. The optimized thickness for the given configuration was found to be 41 mm with the consideration of approximately 50% depth of penetration. The modeled configuration was found to be approximately nine times stronger than the conventional laminated armours. The current study was compared with the previous experimental studies and the results were in good agreement. This agreement solely pertains to the pattern observed and not to individual values. It indicated the difference in % age DOP for the present research and previous studies with the increasing thickness of laminated armour. The trend observed was nearly similar to previous experimental studies. This showed that the DOP was reduced, as the thickness increased. Moreover, the previous studies showed that only ALON (aluminium-oxynitride) and sapphire had the required strength to act as a hard front-faced layer in laminated glass, but the current study improvised it to a Silicon carbide hard front-faced layer also.

Thermal performance improvement of a radial pulsating heat pipe with diverging channels by adopting Tesla valves at various heat fluxes

The thermal performance of a pulsating heat pipe (PHP) can be improved by increasing the flow circulation with the adoption of novel channel designs to minimize flow resistance. This study aimed to improve the thermal performance characteristics of a radial PHP with diverging channels by adopting Tesla valves. The effects of heat flux, condensation temperature, and heat transfer area ratio on the thermal resistance and heat transfer coefficient of the PHP with Tesla valves were measured under different heating and cooling conditions. In addition, the flow behaviors and pressure variations were analyzed for a short time frame. The PHP with Tesla valves exhibited a 17 %-lower thermal resistance than that without Tesla valves owing to the increased flow circulation with preferential movement in one direction. Furthermore, the heat transfer capability of the PHP with Tesla valves increased with increasing condensation temperature and heat transfer area ratio at the same heat flux. In addition, the optimal filling ratios were determined to be 70, 80, and 90 % for heat transfer area ratios of 0.13, 0.08, and 0.05, respectively. Finally, contour maps for the maximum temperature deviation were developed in terms of the heat flux, heat input, and heat transfer area ratio.

All-Three-Dimensionally-Printed AgPd Thick-Film Strain Gauge with a Glass-Ceramic Protective Layer for High-Temperature Applications.

A high-temperature thin/thick-film strain gauge (TFSG) shows development prospects for in situ strain monitoring of hot-end components due to their small perturbations, no damage, and fast response. Direct ink writing (DIW) 3D printing is an emerging and facile approach for the rapid fabrication of TFSG. However, TFSGs prepared based on 3D printing with both high thermal stability and low temperature coefficient of resistance (TCR) over a wide temperature range remain a great challenge. Here, we report a AgPd TFSG with a glass-ceramic protective layer based on DIW. By encapsulating the AgPd sensitive layer and regulating the Pd content, the AgPd TFSG demonstrated a low TCR (191.6 ppm/°C) from 50 to 800 °C and ultrahigh stability (with a resistance drift rate of 0.14%/h at 800 °C). Meanwhile, the achieved specifications for strain detection included a strain sensing range of ±500 με, fast response time of 153 ms, gauge factor of 0.75 at 800 °C, and high durability of >8000 cyclic loading tests. The AgPd TFSG effectively monitors strain in superalloys and can be directly deposited onto cylindrical surfaces, demonstrating the scalability of the presented approach. This work provides a strategy to develop TFSGs for in situ sensing of complex curved surfaces in harsh environments.

Additive Manufacturing of High‐Temperature Preceramic‐Derived SiOC Hybrid Functional Ceramics

High‐temperature capable materials, metals, and ceramics are attracting significant interest for applications in extreme environmental conditions. Herein, a hybrid metal‐reinforced ceramic matrix material consisting of preceramic‐derived high‐temperature SiOC and copper nanoplates is reported, enabling the manufacturing of high‐temperature sensing electronics. The preceramic polymer precursors including polydimethylsiloxane and polydimethylsilane, together with copper nanoplates, are thermally converted into durable copper‐reinforced SiOC ceramics. The presence of copper in SiOC ceramics enhances its electrical conductivity, while SiOC suppresses oxygen uptake and acts as a shield for oxidation to achieve high‐temperature thermal resistance and negative temperature coefficient at high temperatures. A comprehensive electric and sensing performance, combined with cost‐effectiveness and scalability, can facilitate the utilization of hybrid Cu and SiOC composites in high‐temperature electronics.

An experimental study on heat power stored by thermal dissipation in electronic components using thermosyphon integrated hybrid nanocomposite phase change material

This study investigates the heat power stored by the thermal dissipation of electronic components using a thermosyphon integrated hybrid nanocomposite phase change material storage system. The study examines various thermal performances including the percentage of thermal dissipation, thermal resistance and heat transfer coefficient using benzene, deionized water, methanol and methyl acetate as heat transfer fluids, with an intended heat input of 50 – 120 W. The 0.5 wt% copper-titania hybrid nanocomposite particles are dispersed with phase change material (methyl cinnamate) and chosen as hybrid nanocomposite phase change material. The assessment of charging and retrieving characteristics of stored hybrid nanocomposite phase change material has been done by the impact of heat transfer fluids flowing through the copper tube at the different heat inputs. The result findings show that methyl acetate has the maximum percentage of thermal dissipation, low thermal resistance and high heat transfer coefficient of about 99.2 %, 0.311 K/W and 242.36 W/(m2.K) respectively at 120 W. The obtained results are attributed to the low boiling point and enthalpy of vapourization of methyl acetate. The highest heat power stored by hybrid nanocomposite phase change material is discovered as 6.5 W during melting by the impact of vapourized methyl acetate at maximum heat input owing to the higher mass flow rate and lesser time to attain steady state temperature of hybrid nanocomposite phase change material. Also, the developed system promotes thermal management in electronic components along with a minimum power saving of about 5–6 %.

Influence of Alkali Treatment on Microstructure Transformation and Mechanical Properties of Palm-Fiber Cell Wall

ABSTRACT Utilizing agricultural waste and natural fibers minimizes environmental impact and can improve the acoustic and thermal conditions of buildings. Natural fibers can be an alternative to non-biodegradable synthetic sound-absorbing materials. This study aimed to investigate the acoustic and thermal properties of insulating materials made from wool and sugarcane bagasse. Thermal conductivity, thermal resistance, acoustic and moisture absorption, and fire properties of five insulating materials made from sheep wool, goat fiber, camel wool as well as pith and fiber bundles of sugarcane bagasse were determined. The measurement of the sound absorption coefficient was performed in an impedance tube. The thermal resistance and thermal conductivity coefficient were measured according to the ASTM D5334–08 Standard. The findings show that camel wool has the highest sound-absorbing performance, thermal insulation, and fire-resistant properties. The lowest value of the noise reduction coefficient (NRC) was 0.52 for goat fiber, and the highest was 0.74 for camel wool. The maximum sound absorption coefficient of camel wool was 0.95 at a frequency above 1000 Hz. Thermal conductivity varies between 0.038 and 0.046W/(M.K). Hence, all materials tested can be considered thermally insulating. The results showed insulating materials made from wool, especially camel wool, had better performance than fiber and pith of sugarcane bagasse.

Acoustical and Thermal Characterization of Insulating Materials Made from Wool and Sugarcane Bagasse

ABSTRACT Utilizing agricultural waste and natural fibers minimizes environmental impact and can improve the acoustic and thermal conditions of buildings. Natural fibers can be an alternative to non-biodegradable synthetic sound-absorbing materials. This study aimed to investigate the acoustic and thermal properties of insulating materials made from wool and sugarcane bagasse. Thermal conductivity, thermal resistance, acoustic and moisture absorption, and fire properties of five insulating materials made from sheep wool, goat fiber, camel wool as well as pith and fiber bundles of sugarcane bagasse were determined. The measurement of the sound absorption coefficient was performed in an impedance tube. The thermal resistance and thermal conductivity coefficient were measured according to the ASTM D5334–08 Standard. The findings show that camel wool has the highest sound-absorbing performance, thermal insulation, and fire-resistant properties. The lowest value of the noise reduction coefficient (NRC) was 0.52 for goat fiber, and the highest was 0.74 for camel wool. The maximum sound absorption coefficient of camel wool was 0.95 at a frequency above 1000 Hz. Thermal conductivity varies between 0.038–0.046W/(M.K). Hence, all materials tested can be considered thermally insulating. The results showed insulating materials made from wool, especially camel wool, had better performance than fiber and pith of sugarcane bagasse.

Influence of calendering process on the structural mechanics and heat transfer characteristics of lithium-ion battery electrodes via DEM simulations

Elucidating the intricate correlation between calendering, structure, and performance is crucial to comprehending the relationship between performance parameters and process steps of lithium-ion batteries (LIBs). Discrete element method (DEM) simulations were adopted in this work to calculate the interparticle force and stress tensor under incremental calendering process conditions, which revealed the effect of the anisotropy of complex contact force network on the anisotropy of heat transfer within porous electrode. The thermal conductivity of electrode was predicted using porosity to characterize the process–structure–performance correlation. The comprehensive influence of contact number and contact area between particles and current collector determines the magnitude of interfacial thermal resistance and interfacial heat transfer coefficient. For the first time, this work quantitatively analyzed the structural mechanics and heat transfer mechanism during calendering process of porous electrodes, and the results indicate a promising way to optimize and design battery electrode structures.

The effect of thermal insulation from autoclaved aerated concrete on the energy performance of a single-family house

The article examines the effect of thermal insulation from autoclaved aerated concrete on the energy characteristics of a single-family house. Analysis of mathematical models of energy characteristics of external enclosing structures of buildings depending on the thickness of AEROC autoclaved concrete products according to the criteria of heat loss shows that the thermal resistance value of 7.11 m2K/W and the heat transfer coefficient of 0.141 W/(m2K) are achieved using the wall block AEROC D 300 and AEROC Energy thermal insulation panel with a thickness of 200 mm. These indicators correspond to the passive house standard for thermal resistance (Ro ≥ 6.7 m2K/W) and heat transfer coefficient (Uo ≤ 0.15 W/m2K) of external walls, which confirms the feasibility of using AEROC Energy D 150 thermal insulation panels in combination with wall blocks AEROC D 300 for housing construction according to passive construction standards.

Structure Control and Evaluation of Effective Fracture Energy on Alumina-Magnesia Monolithic Refractories Prepared with CaO·6Al<sub>2</sub>O<sub>3</sub> Aggregate

Alumina-magnesium castable refractories are used for the inner walls of molten steel ladles. The main cause of damage to these refractories is thermal shock caused by rapid temperature changes during the loading and unloading of molten steel. Therefore, the thermal shock damage resistance coefficient R'''' is a parameter that expresses the resistance of refractories to thermal shock, and the evaluation of effective fracture energy is important for improving R''''. In this refractory, CaO·6Al2O3 (CA6) is formed from the raw materials alumina and alumina cement; CA6 has the advantage of inhibiting crack propagation and improving mechanical properties. On the other hand, CA6 has the disadvantage of volumetric expansion during formation. Therefore, microstructural changes caused by the formation of CA6 significantly affect the mechanical properties of refractories. In this study, CA6 was used as raw material and replaced with CA6 generated in-situ. The amount of coarse-grained alumina added was adjusted to control the microstructure. The effect of the microstructure change on the effective fracture energy was then evaluated. As a result, the effective fracture energy was improved in the sample with more coarse-grained alumina added, due to the replacement of CA6 aggregate.