Thermal Cycling Conditions Research Articles

Water vapor mass transfer in alginate–graphite bio-based hydrogel for atmospheric water harvesting

This study presents experimental and theoretical investigations on water vapor mass transfer of a novel hydrogel compound based on alginate and graphite. This hydrogel enables rapid, reproducible, and thermally driven cycles for the adsorption and desorption of water vapor from ambient air for atmospheric water harvesting applications. We study the impacts of hydrogel composition on sorption capacity and kinetics using sorption/regeneration experiments under various environmental conditions. Theoretical models based on Fick's law of diffusion and Linear Driving Force are developed and validated with experiments to optimize thermal cycling conditions within the temperature range of 20–100 °C. The bio-based hydrogel exhibited remarkable water uptake, ranging from 0.5 to 0.9 g/g, with RH below 30 and 50 %, respectively. This low-humidity setting enables a water production rate of 1.6–2.9 L/kg of sorbent per day with a low-grade thermal regeneration (60–100 °C). Natural graphite microparticles improve water vapor release kinetics during regeneration, with an effective diffusivity coefficient of around 10−11 m²/s.

High-temperature oxidation behavior of direct-aged bimodal Al2O3-reinforced Inconel625 plasma sprayed composite coatings

Plasma-sprayed (PS) coatings in industrial or aerospace applications are chosen as a technique for enhancing the high-temperature oxidation performance of parts operating under strenuous conditions. However, the presence of microstructural defects and amorphous phases developed in as-sprayed plasma coatings can restrict the potential of such coatings when exposed to thermal cycling conditions. Examining the oxidation performance and microstructural characterization of three heat-treated Inconel 625-Al2O3 plasma-sprayed composite coatings over an ASTM SA210 GrA1 (uncoated) substrate is the goal of the current study: The three prepared compositions are; a) Inconel625-30 wt% micron-sized Al2O3 (INC625-CHT) coating, b) Inconel625-30 wt% nano-sized Al2O3 (INC625-NHT) coating and c) Inconel625-15 wt% micron-sized Al2O3 + 15 wt% nano-sized Al2O3 (INC625-BHT/bimodal) coating. High-temperature oxidation tests were conducted at 900 °C temperature in air for 50 cycles in a simulated environment using a laboratory silica tube furnace. The microstructures and morphologies of the composite coatings in the as-sprayed and oxidized conditions were characterized using SEM, EDX, and XRD techniques. The furnace heat treatment (HT) improves the oxidation resistance of the coatings in order INC625-BHT, INC625-NHT, and INC625-CHT coating by healing interlamellar defects like pores and cracks.

Daily thermal variability does not modify long-term gene expression relative to stable thermal environments: A case study of a tropical fish

Global warming is leading to an increase in the frequency and intensity of extreme weather events, magnifying the breadth of temperatures faced by ectotherms across days and seasons. Despite the importance and ecological relevance of diurnal thermal variability, the vast majority of knowledge on gene expression patterns and physiology stems from animals acclimated to constant temperatures or in the early stages of exposure to a new temperature regime. If heterothermal environments modulate responses differently from constant thermal environments, our existing capacity to forecast impacts of climate warming may be compromised. To address this knowledge gap, we acclimated barramundi (Lates calcarifer) to 23 °C, 29 °C (optimal), 35 °C and to thermal cycling conditions (23–35 °C daily with a mean of 29 °C) and sampled liver and white muscle tissue before acclimation and after 2 and 17 weeks of acclimation. NanoString nCounter technologies were used to measure expression of 20 genes related to metabolism, growth and maintenance of cellular homeostasis. Acclimation to cool and warm conditions caused predictable changes in whole-animal performance (metabolism and growth) and the underlying gene expression patterns. Acclimation to a cycling temperature regime did not change the molecular regulation of metabolism or growth compared with barramundi acclimated to constant 29 °C, nor did it cause any discernible effects on whole-animal performance. However, the heat shock response was higher in the former group, suggesting that barramundi under a daily temperature cycle have an increased need for cellular chaperoning to minimise detrimental effects of temperature on proteins. We conclude that the genetic regulation of metabolism and growth may be more dependent on the mean daily temperature than on the daily temperature range.

Additive manufacturing: Application and validation of machine learning-based process-structure-property linkages in Ti-6Al-4V

In the field of metal additive manufacturing (AM), various processes and heat treatments can yield unique grain morphologies, thereby influencing material properties and machining behavior. In this study, a novel workflow using a machine learning-based approach that combines statistical descriptors of textured AM-process induced microstructure, cutting force model (as a material response), and a data-mining method is established. It is proven to be a valid method for creating process-structure-property linkages for metal AM. This study focuses on two highly varied metal AM processes: Powder bed fusion (PBF, e.g., laser PBF and electron beam PBF) and directed energy deposition (DED, e.g., wire-fed plasma-directed energy deposition). The study also accounted for the effects of post-AM heat treatment and build orientation. It was found that the accuracy of material behavior predictions is highly correlated with AM processing conditions, building orientations, and machining conditions. Specifically, while initially applying PBF training data to DED samples resulted in a 15% root mean square prediction error, this error was subsequently reduced to <1% through cross-training using combined microstructure training data sets. This discrepancy could be attributed to the significantly different thermal cycling conditions in L-PBF and DED, which resulted in highly varied textured microstructures. Residual stresses generated during AM processing and the selection of machining parameters exert the highest impact on the machining behavior. The implications of these findings extend to the use of statistically descriptive microstructures for various AM processing conditions and build orientations in computational methods and other machining learning approaches.

Effect of thermal cycling on the strain and stress distribution of TSVs and solder bumps in stacked package structure

Aerospace exploration requires electronic devices to withstand the test of extreme environments, and it is of great significance to study the reliability of packaged devices at extreme temperatures. In this paper, the Anand model is used to describe the mechanical constitutive behavior of Sn-3.0Ag-0.5Cu (SAC305) solder and through-silicon via (TSV) in a 3D package structure, and the thermal cycling behavior of controlled collapse chip connection (C4) bumps and TSV arrays under thermal cycling from -100 to 120 °C is analyzed. The thermal fatigue life of C4 bumps and TSVs was evaluated according to the modified Coffin-Manson model. The results show that the maximum stress is 50.57 MPa at the contact interface between the C4 bump and the chip, which is caused by local thermal mismatch. The maximum equivalent plastic strain of the key bump is 1.6 × 10−2 and its fatigue life under extreme temperature thermal cycling conditions is about 1366 cycles. The maximum equivalent plastic strain of the TSV array is 2.8 × 10−2, located at the corner of the peripheral TSV, which is the most dangerous position in the TSV array, and its thermal fatigue life is about 1.9 × 106 cycles.

Damage Grading Evaluation of Thermal Barrier Coatings under CMAS Corrosion

Thermal barrier coatings (TBCs) material has excellent high-temperature resistance and heat insulation performance, which plays a vital role in improving the working efficiency and running life of the engine. During the flight, the engine will inhale dust particles in the air. These particles are mostly from siliceous debris, which are usually called calcium magnesium aluminum silicate (CMAS). At present, CMAS corrosion has become one of the important problems affecting the service life of thermal barrier coatings. In this study, conventional yttrium oxide stabilized zirconia (YSZ) coatings and ytterbium oxide and yttrium oxide co-stabilized zirconia (YbYSZ) coatings were prepared by atmospheric plasma spraying. The two coatings were examined under thermal cycling-CMAS coupling conditions and divided into six life stages. The failure modes, CMAS permeation behavior, crack characteristics and mechanical properties of the two coatings at different life stages were evaluated systematically. The experimental results show that the YbYSZ coating has a longer life than YSZ coating under the thermal cycling and CMAS coupling condition, which increases by about 83% compared with the conventional YSZ coating. In the whole life stage, the porosity of YbYSZ coating is always higher than that of YSZ coating. The phase transition is not the reason for the failure and spalling of the coatings. The crack length of the two coatings showed an increasing trend, but the crack length of the YSZ coating was higher than that of the YbYSZ coating, and the crack density of the two coatings showed a “saddle shape”, which was more obvious for the YSZ coating. The YbYSZ coating shows better mechanical properties under the thermal cycling-CMAS coupling condition with the evolution of life.

Formation of nitrided layers in iron under thermal cycling conditions

Formation of nitrided layers in iron under thermal cycling conditions

Rapid and Sensitive Human-Specific DNA Quantitation Using a Microfluidic Amplification Module at the Point-of-Care.

A rapid microfluidic human-specific DNA quantitation assay module was developed for chip-based amplification of the human TH01 and Alu loci in the presence of PicoGreen. The method makes use of the thermal cycler and 488 nm Solid State laser-based optical train that are components of the fully-integrated, sample-in to results out, ANDE Rapid Nucleic Acid Analysis system. The assay was effective in quantitating human DNA from a variety of sample types, including blood, buccal, and forensic touch samples mixed with varying amounts of non-human DNA. The 28-cycle TH01 and 10-cycle Alu reactions were completed in 18 minutes and 7 minutes, respectively. The observed limit of detection (LOD) of the assay is approximately 0.3 ng, and the flexibility of assay design allows an LOD of as little as 0.005 femtograms.Clinical Relevance-We have developed a fully-integrated, sample-in to results-out, Rapid Nucleic Acid Analysis system that characterizes nucleic acid fragments (whether generated by PCR, rt-PCR, sequencing, or SNP reactions) by electrophoresis in plastic microfluidic channels. Here we describe the development, characterization, and validation of the microfluidic quantitation module. The quantitation module is the first that can be incorporated into integrated microfluidic workflows for the analysis of highly-multiplexed clinical diagnostic assays interrogating hundreds of genomic targets in a single sample. In particular, the use of a microfluidic quantitation module allows reaction volumes, thermal cycling conditions, and electrophoretic injection protocols to be determined based on nucleic acid content during and throughout fully-automated processing-dramatically enhancing the power of the fully-automated diagnostic system.

Exploration of Effect of Thermal Cycling Treatment on Mechanical and Tribological Performance of Polyimide Composites

Polyimide (PI) and PI composites reinforced with glass fiber (GF), and aramid fiber (AF) were fabricated with hot-pressing technology. Then polyimide and its composites were treated with a thermal cycling (TC) condition from –50 °C to 150 °C with 300 cycles continuously. Compared with the samples without TC treatment, the fracture morphologies, mechanics, and tribological properties of the samples were studied. The results showed that, based on the fractographic morphologies, the phenomenon of fiber stripping could be obviously observed in the PI composite materials after TC treatment. Compared with before TC treatment, the friction coefficients (FC) and wear rates (WR) of PI and PI composites showed different variations, respectively. In conclusion, TC treatment had a great influence on the morphologies of the worn surface and the composition of transfer film. As the shear force increased, the elemental analysis demonstrated that GF was extruded into the groove.

Study of the resistance of nitrile butadiene rubber to thermal cycling in a hydrocarbon medium

The change in the properties of rubbers 98-1 and RP-10 based on nitrile butadiene rubbers with 17– 20% of acrylonitrile content under thermal cycling conditions in the range from –50 to +80°С is evaluated. The samples are exposed in the air and working hydrocarbon medium of hydraulic oil I-20A in stress-free and deformed states. It has been established that 98-1 rubber is more resistant in air and RP-10 rubber containing a sulfur-peroxide vulcanizing system and UHMWPE demonstrates high durability in a hydrocarbon medium in comparison with first one. The paper shows insignificant deformation on the rubbers properties and deterioration of the frost resistance of rubbers up to its complete loss during thermal cycling in the medium of I-20A hydraulic oil.

Microstructure changes in Sn-Bi solder joints reinforced with Zn@Sn particles in thermal cycling and thermomigration

BackgroundIn the field of electronic packaging, Sn-58Bi solder paste is a promising low-temperature option for step soldering. However, the tendency for the Bi-rich phase to coarsen and segregate poses a significant challenge to the long-term reliability of the solder joints. MethodsThe Sn coated Zn (Zn@Sn) core-shell particles were prepared through a chemical plating process and incorporated into the Sn-58Bi low-temperature solder paste to enhance its reliability. The microstructural and mechanical characteristics of the solder joints were evaluated under thermal cycling and thermomigration conditions to assess their long-term service reliability. Significant findingsThe addition of Zn lowers the nucleation energy and promotes the refinement of the eutectic structure, avoiding a significant reduction in shear strength after thermal cycling. In thermomigration, the heat transfer Q* of Bi is calculated to be 22.5 kJ/mol. The Zn-rich phases hardly move and are evenly distributed within the solder joints, acting like a barrier to prevent the Bi phase diffusing from the hot end to the cold end.

Evaluation of epoxy-based coating degradation under thermal insulation at elevated temperatures on different steel substrates

Corrosion under insulation (CUI) remains one of the most critical issues in the petrochemical industry. In a typical CUI system, protective coatings (organic or metallic) are used primarily as the last barrier to prevent the rapid corrosion of the metallic substrate. However, organic coatings exposed to high operating temperatures and thermal cycling conditions are susceptible to failure and thus require coating performance evaluations under representative thermal insulation conditions. This study presents experimental designs to investigate the degradation of an organic polyamine-cured epoxy coating under accelerated laboratory test conditions. Additionally, a systematic CUI evaluation protocol for high-temperature organic coating performance is presented. The method involved specially designed apparatus to simulate CUI systems and characterisation techniques, such as visual inspection, adhesion test, peel-off test, scanning electron microscopy, electrochemical impedance spectroscopy, and chemical analysis using Fourier-transform infrared spectroscopy, and differential scanning calorimetry. The results showed that polyamine-based epoxy coating experienced thermal degradation starting at temperatures above 130 °C under mineral wool insulation in accelerated and cyclic CUI tests. Chemical degradation was the primary mode of degradation, with the formation of carbonyl functional groups and increased glass transition temperature observed at higher exposure temperatures. The proposed combination of electrochemical, spectroscopic, mechanical, and microscopy techniques allows quantifying coating performance under insulation and subsequently provides insights into predicting coatings' service lifetime.

Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

The paper presents the results of experimental research on the development of a repair technique for a pipeline transporting hydrogen mixed with petroleum vapors, which has been in operation for 25 years at Mozyr Oil Refinery, the largest oil enterprise of the Republic of Belarus. The failure of this pipeline was caused by a crack formed in the weld root and its propagation along the fusion line of the heterogeneous weld joint. The developed technique made it possible to prevent further crack propagation without interrupting the refinery fractionation column operation. Welding of the main weld should be performed on a previously deposited damping layer. The damping layer must be deposited by using welding materials, the welding method and the technique that lead to creating a nonoriented dendritic structure. For this purpose, a welding material that has an energy of crack initiation and propagation greater than the energy of crack propagation in the base metal must be used. The composition of the weld must include chemical elements that inhibit the intensity of diffusion processes and increase the strength of the interatomic forces of the austenitic matrix at the pipeline operating temperature.

Microstructures and shear strengths of W-ball solder joints aged under isothermal and cyclic thermal conditions

Microstructures and shear strengths of W-ball solder joints aged under isothermal and cyclic thermal conditions

Effects of Voids on Thermal Fatigue Reliability of Solder Joints on Inner Rings in Ball Grid Array Packaging by Finite Element Analysis

Under alternating temperatures, the fatigue failure of solder balls caused by the mismatch of the thermal expansion coefficient is a key problem in a Ball Grid Array (BGA). However, the combined effects of the solder ball location and the size of voids within it can seriously affect the thermal fatigue reliability of BGA solder balls, which can be easily ignored by researchers. Firstly, the thermal fatigue reliability of the board-level solder balls was evaluated by a temperature cycling test of the BGA package at -20 °C-+125 °C. The experimental results showed that the thermal fatigue reliability of the outer ring's solder joint was lower than that of the inner ring. Secondly, the reliability of the solder balls in the BGA package was studied under the same thermal cycling condition based on finite element analysis (FEA). The influences of voids on fatigue life were investigated. Generally, a linear correlation between the void content and the fatigue life of the inner rings' solder balls could be identified with a gradually smoothed relationship for solder balls closer to the center. In addition, when the size of the void exceeded a critical volume, the inner ring's solder ball with the void would fail before the outermost ring. The results of FEA showed that the critical void volume ratio from the second to fifth ring increased from 10.5% to 42.3%. This study provides a valuable reference for the influence of voids on the thermal fatigue reliability of BGA solder balls.

Fatigue behavior of 3D stacked packaging structures under extreme thermal cycling condition

In deep space exploration environment, electronic devices face severe tests. C4 solder joints and TSV, as the weak links of the three-dimensional packaging structure, have a significant impact on the reliability of the packaging structure. This work focuses on the typical three-dimensional packaging structure and utilizes finite element software to analyze the influence of extreme thermal cycling on the fatigue life of packaging structure. The results show that under the extreme temperature range of -100∼120 °C, the maximum stress concentration of a typical 3D packaging structure occurs at the interface between the TSV and Si chip, and the TSV and C4 solder joints remote from the center bear greater stress and strain. The maximum stress of TSV appears at the end edge of TSV at the upper left corner. The maximum stress of the C4 welding spot appears on the second welding spot in the rightmost column. The most dangerous TSV fatigue life is 1.07 × 107 cycles calculated by combining the finite element simulation results with the Coffin Manson model. The life of the most dangerous C4 solder joint is 2892 cycles. C4 solder joint is the failure-sensitive location of the three-dimensional packaging structure under extreme ambient temperature, and optimization design is required in the subsequent work to improve its reliable life.

Thermal-Cycling-Induced Si3N4 Damage in Semiconductor Devices Assembled Utilizing a Lead-on-Chip Package

This article shows how fractures in the Si3N4 layer, which comprises the top layer of semiconductor devices encapsulated utilizing a lead-on-chip (LOC) packaging technique, are influenced by changes in the lead-frame materials and thermal-cycling test conditions. Using thermal-cycling tests, it was found that fractures in the Si 3 N 4 layer are the most sensitive to changes in the lead-frame materials at the early stage of thermal-cycling, between -65sup>oC and 150sup>oC. Through SEM examinations and stress simulations, this work shows that adopting a copper lead-frame with a CTE-value similar to that of a package body effectively prevents filler-driven Si3N4 damage, providing semiconductor devices with better reliability margins during thermal-cycling.

Effects of interface cracks on reliability of surface mount technology interconnection in service environment

PurposeSurface mount technology (SMT) is widely used and plays an important role in electronic equipment. The purpose of this paper is to reveal the effects of interface cracks on the fatigue life of SMT solder joint under service load and to provide some valuable reference information for improving service reliability of SMT packages.Design/methodology/approachA 3D geometric model of SMT package is established. The mechanical properties of SMT solder joint under thermal cycling load and random vibration load were solved by 3D finite element analysis. The fatigue life of SMT solder joint under different loads can be calculated by using the modified Coffin–Manson model and high-cycle fatigue model.FindingsThe results revealed that cracks at different locations and propagation directions have different effect on the fatigue life of the SMT solder joint. From the location of the cracks, Crack 1 has the most significant impact on the thermal fatigue life of the solder joint. Under the same thermal cycling conditions, its life has decreased by 46.98%, followed by Crack 2, Crack 4 and Crack 3. On the other hand, under the same random vibration load, Crack 4 has the most significant impact on the solder joint fatigue life, reducing its life by 81.39%, followed by Crack 1, Crack 3 and Crack 2. From the crack propagation direction, with the increase of crack depth, the thermal fatigue life of the SMT solder joint decreases sharply at first and then continues to decline almost linearly. The random vibration fatigue life of the solder joint decreases continuously with the increase of crack depth. From the crack depth of 0.01 mm to 0.05 mm, the random vibration fatigue life decreases by 86.75%. When the crack width increases, the thermal and random vibration fatigue life of the solder joint decreases almost linearly.Originality/valueThis paper investigates the effects of interface cracks on the fatigue life and provides useful information on the reliability of SMT packages.

Evaluation of Solid Particle Erosion of EB-PVD TBCs under Thermal Cycling Conditions Based on a Stochastic Approach

The solid particle erosion behavior of electron-beam physical vapor deposition (EB-PVD) thermal barrier coatings (TBCs) was numerically evaluated under thermal cycling conditions. The erosion rates were calculated based on the mechanics-based formulae where the model parameters are fitted to the temperature-process-dependent test data available in the literature. A stochastic approach was applied to simulate the erosion behavior toward service conditions. The mechanics-based formulae were then validated by experimentally measured temperature and sintering-dependent erosion rates from the literature. The pseudoductile erosion behavior is identified for silica particles in the EB-PVD topcoat (TC) erosion system above the intermediate temperatures (~220 °C) due to the softening of partial molten silica particles, thus leading to an increase in the cutting wear and a decrease in deformation wear. The erosion rates are found to decrease versus temperature but increase versus thermal cycles. Such erosion behavior could be attributed to propagation of sintering cracks induced at elevated temperatures. The parametric calculations show that both erosion and thermal cycling parameters have a profound effect on the erosion mechanism of EB-PVD TC. The erosion rate increases at higher solid particle velocity and accumulated mass but displays a pseudoductile erosion behavior versus variation of impacting angles. Two types of erosion mechanisms were evaluated under different thermal cycling conditions. Under the burner cycling test with a short high-temperature dwell period, the erosion mechanism of EB-PVD TBCs is governed by temperature, while under an isothermal cycling test with a high-temperature long dwell period, the erosion is determined by sintering time. The failure mechanisms of EB-PVD TBCs under solid particle erosion processes are discussed combining internal cracking within topcoat and external erosion on the surface of topcoat.

A comprehensive study of the phase segregation of a urea-based phase change material tested under thermal cycling conditions

Eutectic mixtures are used as PCMs due to the possibility to tailor the melting temperatures and mainly because the phase transition occurs at a unique temperature. Eutectic mixtures are assumed to be congruent melting and solidification materials. Compositional segregation has rarely been reported, when have been researched for its use as PCM. However, the previous premise does not always match the observed facts. The presented work aims to deepen the knowledge regarding the use of eutectic mixtures as PCMs and to determine the influence of operation parameters in the eutectic PCMs potential phase segregation.The eutectic mixture formed by urea and sodium nitrate can be an interesting candidate for use as a phase change material for thermal energy storage in space heating and domestic hot water applications. Nevertheless, the eutectic mixture showed an unforeseen segregation phenomenon when it was exposed to repeated melting-solidification cycles using volumes in the scale of grams. As a result, the phenomenon was studied to determine the potential causes. An experimental campaign was performed to study the urea and sodium nitrate eutectic mixture under different conditions: consisting of thermal cycling using representative masses, and subsequently, the segregated materials and obtained samples were analyzed by different techniques (including XRD, HTXRD, and DSC); and the production of samples under different cooling conditions that were analyzed using microscopy (PLM and SEM). The results established a relationship between the operation conditions, with the resulting crystal structures, which explain the phase segregation in the eutectic mixture. A mitigation measure was determined consisting of mechanical stirring.