Heat Treatment Method Research Articles

Physicochemical Stimuli-Mediated Precipitation Approach for the Modulation of Rifampicin's Dissolution and Oral Bioavailability.

The intricate process of protein binding orchestrates crucial drug interactions within the bloodstream, facilitating the formation of soluble complexes. This research endeavours to improve the dissolution and oral bioavailability of Rifampicin (RMP) by strategically manipulating drug-protein binding dynamics and the hydrophobic characteristics of human serum albumin (HSA). Various precipitation techniques leveraging methanol, ammonium sulfate, and heat treatment were meticulously employed to tailor the properties of colloidal albumin (HSA NPs). The resultant complexes underwent comprehensive characterization encompassing evaluations of hydrophobicity, size distribution, surface charge, and structural analyses through FTIR, TG-DSC, XRD, and morphological examinations. The findings revealed a significant binding affinity of 78.07 ± 6.6% with native albumin, aligning with prior research. Notably, the complex RMP-HSA NPs-M13, synthesized via the methanolic precipitation method, exhibited the most substantial complexation, achieving a remarkable 3.5-fold increase, followed by the ammonium sulfate (twofold) and heat treatment (1.07-fold) methods in comparison to native albumin binding. The gastric simulated media exhibited accelerated drug release kinetics, with maximal dissolution achieved within two hours, contrasting with the prolonged release observed under intestinal pH conditions. These findings translated into significant improvements in drug permeation, as evidenced by pharmacokinetic profiles demonstrating elevated Cmax, AUC, t1/2, and MRT values for RMP-HSA NPs-M13 compared to free RMP. In summary, this innovative approach underscores the potential of precipitation methods in engineering stable colloidal carrier systems tailored to enhance the oral bioavailability of poorly soluble drugs, offering a pragmatic and scalable alternative to conventional surfactants, polymers, or high-energy methods for complex formation and production.

Formation mechanism of cation-vacancy microenvironments and the effect on hydrogen transfer reaction of 5-hydroxymethylfurfural

Two Cu/ZrO2 catalysts defect with different microenvironments and electronic structures (CZ-ag-70 and CZ-va catalysts) were synthesized by the same oxalic-acid-complexation-based method but different heat-treatment methods, and they were used to catalyze the hydrogen-transfer reaction between 5-hydroxymethylfurfural (HMF) and isopropanol. The structure–activity relationship of each catalyst was analyzed, and defect microenvironments were found to have an important influence on the product of the hydrogen-transfer reaction. The CZ-ag-70 catalyst was rich in Cuδ+- VZr+ interfacial sites (the interfacial sites between electron-deficient copper active sites (Cuδ+)) and electron-free zirconium vacancies (VZr+), and it was conducive to the formation of dehydroxylation product 2,5-dimethylfuran (DMF). Specifically, the ca-ag-70 catalyst achieved 100 % HMF conversion and 82.2 % DMF selectivity. On the other hand, the CZ-va catalyst was rich in single-electron zirconium vacancies (VZr∙), and it was conducive to the generation of reductive-etherification product 2,5-bis(propoxymethyl)furan (BPMF) (100 % HMF conversion and 55 % BPMF selectivity). Through X-ray diffraction spectrum (XRD), electron spin resonance (ESR), hydrogen temperature-programmed reduction (H2-TPR), in-situ Fourier-transform infrared spectroscopy (in-situ FTIR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) analyses, the structure of the CZ-ag-70 catalyst and the mechanism of defect formation in the catalyst were analyzed. The precursor of the CZ-ag-70 catalyst first formed a copper-doped zirconium oxalate substrate. Then, under 500 ℃ reducing atmosphere, the substrate was converted into a copper-doped tetragonal-zirconia carrier, some of the copper species doped into the crystal lattice of the tetragonal-zirconia carrier were reduced, and the copper species migrated to the surface of the carrier, forming Cuδ+- VZr+ interfacial sites. The electrons around the zirconium vacancy of the CZ-ag-70 catalyst are in a completely delocalized state and Cu+ gains electrons which in turn produces Cuδ+- VZr+ interfacial sites.

Dehydration Achieving the Iron Spin State Regulation of Prussian Blue for Boosted Sodium-Ion Storage Performance.

Prussian blue analogs (PBAs) show promise as cathodes for sodium-ion batteries due to their notable cycle stability, cost-effectiveness, and eco-friendly nature, yet the presence of interstitial water limits the specific capacity and obstructs Na+ mobility within the material. Although considerable experimental efforts are focused on dehydrating water for capacity enhancement, there is still a deficiency of a comprehensive understanding of the low capacity of low-spin Fe resulting from interstitial water, which holds significance in Na+ storage. This study introduces a novel gas-assisted heat treatment method to efficiently remove interstitial water from Fe-based PBA (NaFeHCF) electrodes and combines experiments and theoretical calculations to reveal the iron spin state regulation that is related to the capacity enhancement mechanism. This dehydration strategy significantly enhances battery capacity, especially the portion at higher voltages (3.4-4.0V). The increase in capacity is attributed to the following factors: an enhanced proportion of Fe2+, reduced water content which facilitates faster charge transfer, and the activation of low spin Fe2+. The optimized NaFeHCF demonstrated impressive half-cell performance of retaining 87.3% capacity after 2000 cycles at a 5C rate and achieving 100mAhg-1 capacity over 200 cycles when being paired with hard carbon, exhibiting its practical potential.

Modulation of Interlayer Nanochannels via the Moderate Heat Treatment of Graphene Oxide Membranes.

In response to the phenomenon of interlayer transport channel swelling caused by the hydration of oxygen-containing functional groups on the GO membrane surface, a moderate heat treatment method was employed to controllably reduce the graphene oxide (GO) membrane and prepare a reduced GO composite nanofiltration membrane (mixed cellulose membrane (MCE)/ethylenediamine (EDA)/reduced GO-X (RGO-X)). The associations of different heat treatment temperatures with the hydrophilicity, interlayer structure, permeability and dye/salt rejection properties of GO membranes were systematically explored. The results indicated that the oxygen-containing groups of the GO membrane were partially eliminated after heat treatment, and the hydrophilicity was weakened. This effectively weakened the hydration between the GO membrane and the water molecules and inhibited the swelling of the oxidized graphene membrane. In the dye desalination test, the MCE/EDA/RGO membrane exhibited an ultra-high rejection rate of over 97% for methylene blue (MB) dye molecules. In addition, heat treatment increased the structural defects of the GO membrane and promoted the fast passage of water molecules via the membrane. In pure water flux testing, the water flux of the membrane remained above 46.58 Lm-2h-1bar-1, while the salt rejection rate was relatively low.

Preparation of low thermal expansion, transparent LAS glass-ceramics via simplified heat-treatment method

Li2O–Al2O3–SiO2 (LAS) glass-ceramics are commercially significant due to their unique microstructure and exceptional properties, including near-zero thermal expansion coefficient, making them suitable for a wide range of applications. However, the content of SiO2 and Al2O3 in the composition of LAS glass is very high, which leads to high viscosity and very difficult melting of this type of glasses. In order to reduce the melting temperature of the glass, use of relatively high Na2O in the basic glass composition allows high-quality glass to melt. Employing a simplified heat-treatment method, LAS glass-ceramics are prepared with Australian spodumene as the primary material. By exploring the effect of crystallization temperature on the structures and properties of the resulting LAS glass-ceramics, samples with excellent comprehensive properties are achieved. The prepared glass-ceramics are thoroughly characterized using DSC, XRD, FTIR, SEM, and TEM, along with assessments of their viscosity, thermal, optical, and mechanical properties. Relatively more Na2O is introduced into the glass compositions, which can lower the melting temperature of the glass to below 1600 °C. The basic glass is annealed at 700 °C for 2 h, nucleation phenomenon Nucleation phenomenon can be generated in the LAS glasses. When the microcrystalline temperature of glasses increases from 835 °C to 910 °C, the main crystalline phase of glass-ceramics changes from β-quartz solid solution to β-spodumene solid solution. The change in the main crystal phase has significantly affected the properties of glass-ceramics. When the crystallization temperature is below 860 °C, the glass-ceramics exhibit a low negative expansion coefficient (<-0.5 × 10−6 K−1), high visible light transmittance (>85 %), and excellent average flexural strength (173.3 MPa).

High performance SiOx nano-film via rapid heat treatment method as anode material for lithium ion batteries

SiOx (x = 0.61, 0.87 and 1.3) thin film anodes with different oxygen contents were prepared by radio frequency plasma enhanced chemical vapor deposition (PECVD) by adjusting the SiH4/N2O (R) gas flow ratio. The introduction of oxygen can alleviate the volume expansion during discharge/charging at the expense of the cycle-specific capacity. On this basis, rapid thermal process (RTP) of SiOx films at different temperatures was continued. A certain heat treatment is conducive to release the compressive stress accumulated in the deposition process of the film, reducing the impurity molecules in the film, breaking the hanging bonds attached to the film in the preparation process, and improving the overall mechanical properties of the film, so as to improve the cyclic stability and rate performance of the film. After the experiment, the SiO0.61 film was used as the substrate for RTP of the film. The film after RTP at 600 °C had a discharge specific capacity of 1107 mAh g-1 after 100 cycles at 0.5 C current density, which was 352 mAh g-1 higher than that of SiO0.61 without heat treatment.

CO2 Laser Crystallization in Ambient for Highly Efficient FAPbI3 Perovskite Solar Cells.

Metal halide perovskite solar cells have achieved tremendous progress and have attracted enormous research and development efforts since the first report of demonstration in 2009. Due to fabrication versatility, many heat treatment methods can be utilized to achieve perovskite film crystallization. Herein, 10.6µm carbon dioxide laser process is successfully developed for the first time for perovskite film crystallization. In addition, this is the first time formamidinium lead triiodide solar cells by laser annealing under ambient are demonstrated. The champion cell produces a power conversion efficiency of 21.8%, the highest for laser-annealed perovskite cells. And this is achieved without any additive, passivation, or post-treatment.

Influence of discrete laser surface melting on hot cracking behavior and mechanical properties of Q235 steel

Modern industries demand higher mechanical properties from components. Traditional heat treatment methods often suffer from drawbacks such as high production costs, time-intensive processes, and labor-intensive procedures. The integration of bionic engineering with laser surface melting has given rise to Discrete Laser Surface Melting (DLSM) technology, effectively mitigating these shortcomings. Previous research has substantiated the capability of this technology to significantly enhance various metal properties. This study employed an Nd:YAG pulsed laser for the DLSM treatment of Q235 steel. The discrete laser surface melted (DLSMed) units were prepared on Q235 steel samples. Subsequent analysis utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) to examine the microstructure and chemical composition of the DLSMed samples. Surface profilometry, hardness testing, and X-ray stress testing were conducted to measure surface roughness, microhardness, and residual stress, respectively. Mechanical properties were evaluated using tensile and impact testing machines. Experimental findings revealed that the DLSMed sample's surface could be divided into three regions: the melting zone, the heat-affected zone (HAZ), and the substrate. The microstructure of the melting zone consisted of refined martensite. The depth and width of the DLSMed units exhibited a certain regularity with variations in the defocus distance. Increasing the defocus distance positively impacted grain refinement and hardness but also led to an increase in surface roughness. Residual stress increased within a specific defocusing range, but beyond this range, its variation lost regularity. Hot cracking behavior within the DLSMed unit encompassed four stages: crack nucleation, propagation, healing, and decomposition. Different defocusing distances and the distribution of DLSMed units significantly affected the tensile strength and impact toughness of the samples. As the defocusing distance increased, the tensile and yield strength of DLSMed samples with transverse units gradually decreased. In contrast, samples with longitudinal units showed a trend of first decreasing and then increasing in tensile and yield strength. The distribution of DLSMed units played a significant role in improving the tensile properties of Q235 steel. The contribution of three factors to the impact performance of DLSMed samples was ranked from high to low as hardness, grain size, and yield strength ratio. The soft phase (substrate) could absorb impact energy and convert it into strain energy stored in the DLSMed sample. Only when the distribution of DLSMed units (hard phases) aligned with the tensile direction could they effectively limit the plastic deformation and enhance the mechanical properties of Q235 steel. However, an increase in defocusing distance led to increased brittleness, deteriorating the mechanical properties of the DLSMed samples. Finally, this study unveiled the strengthening mechanisms of DLSMed samples, providing valuable insights for future applications in enhancing the mechanical properties of metals.

Impact of Heat Treatment on the Mechanical Properties and Fracture Morphology of Ti555211 Alloy.

Heat treatment is important for optimizing the strength performance and improving the toughness of titanium alloys. In this study, we investigated the impact of three heat treatment methods (β-annealing, double annealing, and solid-solution and aging treatment) on the mechanical properties and fracture morphology of Ti555211 titanium alloy. The results show that after β-annealing treatment, the alloy retains a high strength, while showing almost no ductility, and no yield strength. The alloy after double annealing has a high elongation rate (~54%) and lower strength. After solid-solution and aging heat treatment, the alloy was able to retain both high strength and a certain degree of ductility. The optimal heat-treatment process is solid-solution treatment at 820 °C/2 h and aging at 560 °C/12 h, which results in a maximum tensile strength of 1404 MPa and an elongation rate of 11%.

Immobilization of 137Cs in NaY type zeolite matrices using various heat treatment methods

The accumulation of liquid radioactive waste presents a significant global challenge, necessitating effective strategies for safe management. This study investigates the immobilization of 137Cs radionuclides, a prominent component of liquid radioactive waste, in ceramic matrices based on 137Cs-saturated NaY Faujasite zeolite. Various thermal methods were employed, including cold pressing and sintering, cold pressing and sintering with microwave assistance, hot pressing, and spark plasma sintering, to enhance immobilization capabilities. Zeolite powder was saturated with 137Cs radionuclides using an adsorption technique with low-activity model liquid radioactive waste. In-situ XRD and dilatometry methods were used to study the thermal behavior during NaY Faujasite annealing. The influence of calcination temperature on lattice parameters and crystallite size was assessed. Immobilization effectiveness was evaluated through relative density, Vickers microhardness, compressive strength, and metal ion leaching kinetics. Mechanistic evaluation was performed using XRD and SEM-EDX studies. Results showed that spark plasma sintering exhibited the highest efficiency for immobilizing 137Cs radionuclides in NaY Faujasite matrices. This research contributes to liquid radioactive waste management by providing insights into the thermal behavior and enhanced immobilization capabilities of ceramic matrices.

Investigating Different Heat Treatment Methods to Enhance the Mechanical Properties of 9254 Steel

This study investigates the impact of varied heat treatment parameters on the mechanical and metallurgical characteristics of 9254 steel. Different cylindrical specimens underwent controlled heat treatments targeting three different phases. The interplay of time and temperature was systematically explored to understand their influence on bending strength, bending deflection, hardness, and microstructural evolution. The results revealed that a partially tempered martensitic structure exhibiting an exceptional ultimate strength of 4308 MPa. Achieving this involved a heat treatment, starting at 900°C for 30 minutes, followed by rapid cooling in an oil bath, quenching at 165°C for 5 minutes, annealing at 180°C for 60 minutes, and gradual air-cooling. This treatment regimen produced a specimen with a desirable combination of mechanical properties, showcasing its potential significance in advanced engineering applications.

Novel method and apparatus for evaluating knife performance in meat processing environments

Employees in food processing plants, especially in meat and fish processing facilities, often experience physical strain when using hand knives for manual tasks, leading to musculoskeletal disorders (MSDs). This global issue has prompted research into objective indicators of knife sharpness to optimize sharpening methods and assess blade quality accurately. We introduce novel metrics of hand knife sharpness and edge retention that are derived from force and torque measurements during cutting trials realized on the specifically designed experimental rig and with kinematics based on recordings of real workers. The new method and metrics provide valuable insights into blade quality, sharpening effectiveness, and edge retention, enabling comparisons among knives, steel grades, and heat treatment methods. Our study demonstrates the practical importance of these metrics for improving knife quality control processes in meat processing facilities, ultimately enhancing worker safety and operational efficiency.

High-alumina and low-lithium glass-ceramics modulated by heat treatment and its structural evolution mechanism

In this work, one high-alumina and low-lithium glass-ceramic was successfully developed. The crystal phase, structure and properties of glass-ceramics were precisely modulated by heat treatment. DSC, XRD, TEM and SEM were used to investigate crystallization behavior and the results show that a high alumina content can refine crystal particles. Additionally, FTIR, SAXS NMR and XPS were used to investigate the effect of heat treatment on structure and its modulation mechanism was systematically analyzed. The findings indicate that crystallinity is positively correlated with the glass network polymerization degree. Moreover, the properties of product were evaluated using Vickers hardness and transmittance tests, revealing that the mechanical properties of glass-ceramics could be improved while maintaining transmittance with appropriate heat treatment. Ultimately, this method of heat treatment to modulate glass-ceramics properties provides valuable guidance for high-performance glass-ceramics development.

Improvement of apparent IFSS and specific modulus of CNT yarns

Due to the high strength of carbon nanotubes (CNTs) significant effort has been devoted to incorporating them into fibers and composites. To maximize their potential in these areas, there must be strong interactions between the CNT structures and the matrix of the composite. For CNT yarn, progress in this area has been limited. In this work, we present a method for modifying CNT yarn which improves the apparent interfacial shear strength (IFSS) by up to 45 %, as measured by single yarn pullout testing. An ammonium peroxide mixture (APM) treatment method is used to modify the yarn, and this is followed by treatment with commercial sizing agents. A tensioned heat treatment method is also employed to limit the effect of APM treatment on strength and modulus. This method increased the specific modulus of CNT yarns by as much as 16 %. The combined heat and chemical treatments yield increases as high as 43 % in IFSS and 6 % in specific tensile modulus while tempering the decreases in specific tensile strength. The yarn is characterized by SEM, EDS and Raman spectroscopy to show surface carbon being removed from the yarn, seemingly without damaging the CNT structures in the yarn. The main mechanism for IFSS increase appears to be removal of non-graphitic material from the yarn and slight oxidation of the yarn surface. The increase seen in IFSS has the potential to improve the performance of CNT yarn/polymer matrix composites for aerospace applications.

KAWALAN PENCEGAHAN PENCEMARAN KUTU TERHADAP PRODUK TEPUNG BAGI KESEJAHTERAAN PENGGUNA: KAJIAN EMPIRIKAL DI KILANG TEPUNG

Wheat flour has a certain shelf life and cannot be stored for too long in one storage or warehouse. Wheat flour will naturally attract pests such as beetles and fleas to lay eggs and breed in the flour product. Various strategies have been used by the industry to control the continued occurrence of mealybug contamination, one of which is heat treatment methods. Therefore, this study aims to analyze the efficiency of using heat treatment as an alternative to preventing the breeding of lice in wheat flour. Experiments and observation methods are used as the main data collection and supported by the examination of important documents from the industry to obtain in-depth information about the subject of the study. While the thematic analysis method has been used with the help of atlas ti version 23 software. The results of the study show that there are four main processes that need to be carried out in the process of preventing mealybugs using heat treatment, namely carrying out the cleaning operation of flour residues, placing live ticks at the heat contact point, heat treatment carried out by blowing high-temperature air from the bottom of the storage room and evaluating the effectiveness of heat treatment in eliminating mealybugs. This process is seen to be successful in helping the industry control the breeding of lice in the flour and further increase the productivity and reliability of flour production over time.

Synergy of strength-ductility in a novel Al-Zn-Mg-Cu-Zr-Sc-Hf alloy through optimizing hierarchical microstructures

The strength improvement in the heat-treatable Al-Zn-Mg-Cu alloys is generally achieved by increasing the volume fraction of nanoprecipitates and reducing the grain size. However, utilizing one of them usually leads to a drastic decrease in ductility. Herein, we architect a hierarchical microstructure integrating bimodal grain structures, nanoprecipitates, and hard-brittle coarse particles wrapped by ductility coarse grain (CG) bands via conventional cold rolling (CR) deformation and heat treatment methods to break the strength-ductility dilemma in the Al-8.89Zn-1.98Mg-2.06Cu-0.12Zr-0.05Sc-0.05Hf (wt.%) alloy. The results reveal that the coupling of high-volume fraction (∼1.2%) nanoprecipitates, ∼52% narrow CG bands, and most coarse particles encapsulated by CG bands contribute to the 45% CR sample with outstanding overall mechanical properties (a tensile strength of 655 MPa, a yield strength of 620 MPa, and an elongation of 15.5%). Microstructure-based strength analysis confirms that the high strength relates to a trade-off between the hierarchical features, namely high-volume fraction nanoprecipitates to counterbalance the strength loss caused by grain coarsening. The excellent ductility is due to the introduction of medium CG content with a narrow width that can trigger a cross-scale strain distribution during plastic deformation, suppressing the catastrophic failure in the fine grain (FG) regions and facilitating the dimple fracture along the CG bands. This study proposes a feasible approach for tailoring hierarchical microstructures in Al-Zn-Mg-Cu alloys to achieve a superior strength-ductility combination.

Characterization of Cr-TiB2 composite coating on AISI 1045 steel using hybrid deep neural network-based sandpiper optimization algorithm

The scope of this study is to enhance the performance of AISI 1045 steel for demanding marine applications like connecting rods, axles, and wear-resistant components. Traditional heat treatment methods, including boriding, surface induction hardening, and tempering, improve the steel’s surface hardness. Additionally, the Tungsten Inert Gas (TIG) coating process develops a novel Cr- TiB2 composite coating on the heat-treated AISI 1045 stainless steel. The investigation explores the influence of varying TiB2 content (10%, 20%, and 30%) on the mechanical properties of AISI 1045 steel. Microhardness and tensile characteristics are analyzed, considering the impact of TiB2 percentage. Surface morphology and interfacial bonding are examined using Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDAX). Results reveal notable improvements, including a 2.65 times increase in microhardness compared to untreated AISI 1045 steel, uniform TiB2 distribution, and a crack-free coating. The addition of TiB2 particles in the Cr- TiB2 composite coating enhances microhardness. Improved mechanical properties are attributed to surface treatments, incorporation of hard and wear-resistant materials (Cr and TiB2) in the composite coating, microstructure modifications, and crack prevention, collectively resulting in increased hardness, wear resistance, and durability. Furthermore, this study introduces a novel hybrid Deep Neural Network-based Sandpiper Optimization Algorithm (DNN-SOA) for predicting experimental outcomes with superior accuracy. This research not only enhances the understanding of the coated steel’s mechanical properties but also presents an innovative predictive model for future material engineering applications, demonstrating the significance of advanced heat treatment and a novel composite coating in improving AISI 1045 steel performance.

Novel engineered HER2 specific recombinant protein nanocages for targeted drug delivery.

Protein nanocages resemble natural biomimetic carriers and can be engineered to act as targeted delivery systems, making them an attractive option for various drug delivery and biomedical applications. Our research investigated the genetic link of a specific anti-HER2 peptide (LTVSPWY) to the exposed N-terminal region of the maize (Zea mays) ferritin 1 (ZmFer1) protein nanocage, employing either a 7-amino acid (for LTVS-ZmFer1) or 16-amino acid (for LTVS-L-ZmFer1) linker. We utilized a heat treatment method to load the chemotherapeutic drug doxorubicin into the protein nanocage. The construct with the longer linker (LTVS-L) produced a greater amount of soluble protein nanocage and was selected for further experiments. The average size, polydispersity index, and zeta potential of the engineered protein nanocage were 19.01nm, 0.168, and - 2.13 mV, respectively. The LTVS-L-ZmFer1 protein nanocage exhibited excellent thermal stability, withstanding temperatures up to 100°C with only partial denaturation. Furthermore, we observed that cellular uptake of the LTVS-L-ZmFer1 protein nanocages in HER2-positive breast cancer cells was significantly higher compared to ZmFer1 after labeling with FITC (fluorescein isothiocyanate) (P-value = 0.0001). In addition, we observed a significant decrease in the viability of SKBR3 cells when treated with DOX-loaded LTVS-L-ZmFer1 protein nanocages compared to cells treated with DOX-loaded ZmFer1 protein nanocages. Therefore, this new treatment strategy may prove to be an effective way to reduce both the side effects and toxicity associated with conventional cancer treatments in patients with HER2-positive breast cancer.

Influences of the composition design on the microstructure and properties of laser additive manufacturing TiAl alloy coatings

The utilization of titanium aluminide (TiAl) alloys is widespread in the high-temperature sectors of the aerospace industry, despite their challenging manufacturing process and inherent low toughness. Laser additive manufacturing (LAM), as a solution to these challenges, enhances the capability to form complex components and mechanical properties. The influence of process parameters, heat treatment methods, and reinforcing components on the microstructure of TiAl alloys was studied during the LAM process. The principles of designing TiAl alloys were emphasized from the action mechanism of reinforcing components. A classification standard for the component design was proposed based on the different roles of β-stabilizing elements, α-stabilizing elements, rare earth elements, and composites (a combination of the aforementioned components). Furthermore, the work discussed the evolution mechanism of the microstructure and the strengthening mechanism of mechanical properties in TiAl alloys prepared using LAM. These included solid solution strengthening, precipitation strengthening, grain boundary strengthening, grain refinement, and lattice distortion toughening. Finally, future research directions in LAM TiAl alloys were proposed—the innovative design of TiAl alloys through the structural or interfacial control, the development of multiscale characterization techniques for microstructures, and the advancement of high-performance TiAl alloys using data-driven machine learning approaches.

Progressive Induction Hardening: Measurement and Alteration of Residual Stresses

Progressive induction hardening is an in-line steel heat treatment method commonly used to surface harden powertrain components. It produces a martensitic case layer with a sharp transition zone to the base material. This rapid process will induce large residual stresses, where a compressive state in the case layer will shift to a tensile state in the transition zone. For fatigue performance, it is important to quantify the magnitude and distribution of these stresses, and moreover how they depend on material and processing parameters. In this work, x-ray diffraction in combination with a layer removal method is used for efficient and robust quantification of the subsurface stress state, which combines electropolishing with either turning or milling. Characterization is done on C45E steel samples that were progressively induction hardened using either a fast or slow (27.5 or 5 mm/s, respectively) scanning speed. The results show that although the hardening procedures will meet arbitrary requirements on surface hardness, case depth and microstructure, the subsurface tensile stress peak magnitude is doubled when using a fast scanning speed. However, the near-surface compressive residual stresses are comparable. In addition, the subsurface tensile residual stress peak is compared with the on-surface tensile stresses in the fade-out zone.