Decrease In Hardness Research Articles

Non-monotonic fluctuation of structural heterogeneity in metallic glass due to cyclic rapid heat treatment

Flash-annealing (FA) of metallic glasses (MGs) allows one to modulate their disordered structure. Here, we have flash-annealed a CuZr-based MG below the glass transition temperature at different cycles and generated MGs with various heterogeneous structures. We quantified the glassy structure via the relaxation enthalpy, ΔrelH, which did not significantly change for MGs flash-annealed at a low number of cycles. Their hardness monotonically reduced. However, when more than ten FA cycles were applied, ΔrelH, perceivably decreased, while corresponding hardness increased. High-energy x-ray diffraction analysis revealed that the medium-range ordering of the corresponding structure initially rose and then decreased with an increasing number of FA cycles. This structural change is accompanied by first a hardness decrease followed by an increase. Molecular dynamics simulations showed that throughout the shift from low to high cycles, the structural non-uniformity changed from being non-uniform to more uniform. Through a combination of experiments and simulations, we have shown the non-monotonic relationship between the structural heterogeneity of MGs and cyclic treatments, contributing to a better understanding of the relationship between structural control techniques, microstructure, and properties.

Improving the quality of steamed bread with whole soybean pulp: Effects of ultrasonic treatment on protein structure and reduction of beany flavor

Incorporation of whole soybean pulp (WSP) into wheat flour has been shown to improve the nutritional profile of steamed bread. However, this substitution often disrupts the protein network and introduces an undesirable beany flavor, compromising the overall quality of the steamed bread. This research explored the impacts of varying ultrasonic power levels on the quality of steamed bread containing WSP (WSPSB), with the goal of improving both the protein network structure and the flavor profile. The findings indicated that at an ultrasonic power of 300 W, WSPSB had an 18.10 % decrease in hardness and a 14.93 % increase in specific volume compared to the 0 W. Results from CLSM, SDS-PAGE, fluorescence intensity, surface hydrophobicity, and FTIR spectroscopy revealed that ultrasonic treatment modified the secondary protein structure by increasing the proportion of β-sheets and random coils. These changes facilitated better integration of soybean protein and gluten, thereby strengthening the steamed bread’s protein network. Furthermore, analyses of volatile flavor components, molecular docking, and correlation studies indicated that alterations in the protein structure mitigated the binding of beany flavor components to proteins, leading to significant reductions in their presence—specifically, a 7.12 % decrease in 1-Octen-3-ol and an 8.47 % decrease in Furan, 2-pentyl-. Overall, ultrasound treatment effectively refined the protein network and mitigated the beany flavor in steamed bread, thereby improving its quality.

Foaming purees as a strategy to modify oral processing time.

Food structure modification by increasing viscosity or adding heterogeneity to the food product has shown to effectively change food oral processing. In this study, it was hypothesized that the addition of gas to purees could affect oral processing. This was achieved by creating different structures in purees using a gas syphon, vacuum and syphon+vacuum. The physical properties of the puree (density, flow and mechanical properties) as well as oral processing characteristics, sensory perception and hunger profiles were investigated. Physical measurements showed that the incorporation of gas affected the puree structure as evidenced by a decrease in viscosity, hardness and consistency of the purees. At the oral level, these foamed purees took longer to swallow, which was also reflected in a lower eating rate and slightly lower amount consumed. These changes did not affect hunger or satiety. Therefore, this technique could be beneficial for people who need to eat smaller amounts of food, or for people with swallowing problems, for whom more time in the mouth is recommended without an increase in sensory satiety.

Influence of Low-Temperature Stress-Relieving Treatment in the Fatigue Life of Components Produced by Laser Powder Bed Fusion in AlSi10Mg

This study investigates the impact of low-temperature stress-relieving treatment on the fatigue life of AlSi10Mg components produced by Laser Powder Bed Fusion (L-PBF). The research focuses on a bicycle crank arm, comparing its performance in as-built and heat-treated conditions. The heat treatment involved stress-relieving at 250 °C for 2 h, followed by water quenching. The study found that the as-built condition exhibited a supersaturated Si cellular-dendritic microstructure, while the heat-treated condition showed coarsening of β-Mg2Si phases and Si precipitates. This morphological change led to a decrease in hardness and an increase in ductility. Fatigue tests demonstrated that the heat-treated crank arms achieved the target of 100,000 cycles without failure, unlike the as-built samples, which failed prematurely. The fractography analysis identified surface porosity as the primary crack initiation site. The findings suggest that low-temperature stress-relieving treatment can enhance the fatigue performance of L-PBF AlSi10Mg components by reducing residual stresses and improving defect tolerance.

Development of instant jelly powder from elephant foot yam (Amorphophallus oncophyllus) and roselle (Hibiscus sabdariffa L.) as a functional food for diabetes mellitus patients

Elephant foot yam (Amorphophallus oncophyllus) is one of Indonesia’s most widely grown agricultural commodities. It has a myriad of benefits, especially as a functional food for people with diabetes mellitus. Roselle (Hibiscus sabdariffa L.) is a flowering herb rich in polyphenols and anthocyanins with antioxidant and antidiabetic potentials. Therefore, the aim of this study was to create a functional food that is suitable for diabetes mellitus patients. In this study, a functional food product in the form of instant jelly powder was developed from the yam and roselle. Glucomannan extract, obtained from the yam flour by leaching, was tested using a Fourier-transformed infrared (FTIR) spectrophotometer (qualitative) and determined the content. Three formulas with different amounts of glucomannan and iota carrageenan were developed to determine the most optimized formulation. The most optimized formulation was determined based on organoleptic characteristics and the results of the gel strength and hardness, total phenolic content (TPC), and antioxidant activity tests using the ABTS (2,2'-azino-bis(3 ethylbenzothiazoline-6-sulfonic acid) assay. Glucomannan extraction produced a 92.40% yield, with 46.32% glucomannan content. The spectrophotometric analysis indicated the presence of glucomannan in the extract, and further tests showed it increased with the decrease in gel strength and hardness. It was found that formula I produced the best jelly texture with a total phenolic content of 0.30% GAE (formula II 0.13% GAE; formula III 0.27% GAE) and an ABTS radical scavenging activity of 90.51% (II: 73.49%; III: 88.16%). In conclusion, formula I containing 6.35 g of carrageenan, 2.12 g glucomannan, 1.5 g roselle, 0.03 g citric acid, and 0.003 g sucralose has the best composition to create the most elastic and firm jelly texture with the highest phenolic content and radical scavenging activity.

Elucidation of The Effect of Flossing on Improving Joint Range of Motion

Flossing has been hypothesized to improve joint range of motion (flexibility), potentially through enhanced fascial gliding, although this mechanism remains speculative. This study aimed to clarify the effect of flossing, a new type of myofascial release, on joint range of motion by focusing on tissue gliding properties. This study involved 14 healthy participants (aged 18-25 years) who performed two types of active exercises with floss bands wrapped around their lower legs. As a control, the participants performed the same active exercises on different days without floss bands. Measurements taken before and after the intervention included ankle dorsiflexion range of motion, ankle plantar flexion maximum voluntary contraction, medial head of the gastrocnemius muscle thickness using ultrasound, and fascial hardness at five locations according to depth. Lower leg flossing significantly increased ankle dorsiflexion range of motion by 28.3 ± 19.9% (control: 14.6 ± 12.4%, P = 0.04, d = 0.83). No significant changes were observed in maximum voluntary plantar flexion contraction or overall muscle and fascial hardness. However, the rate of change in hardness showed a trend toward reduction in the superficial fascia and the upper and middle gastrocnemius muscles, with the upper gastrocnemius muscle exhibiting a statistically significant decrease in hardness (P = 0.05). Flossing showed trends toward reducing superficial muscle and fascial hardness, particularly in the superficial fascia and the upper gastrocnemius muscle, although not all changes were statistically significant. This suggests that potential improvements in intertissue gliding around the fascia could contribute to an increased range of motion.

МЕТОДОЛОГИЧЕСКИЕ ОСНОВЫ МАТЕРИАЛОВЕДЧЕСКОЙ ОЦЕНКИ КАЧЕСТВА СМАЗОЧНЫХ СРЕД ДЛЯ НАГРУЖЕННЫХ СОПРЯЖЕНИЙ МАШИН И МЕХАНИЗМОВ. Сообщение 2. Влияние состава смазочных сред на структурно-фазовое состояние зоны деформации металлических трибосопряжений и их антифрикционные свойства

The results of experimental studies of deformation and diffusion in the surface layers of metallic frictional couples, which form the experimental and theoretical basis of the materials science approach to the quality evaluation of lubricants, are presented. The concepts of the component’s role for the lubricating medium in the implementation of the plasticizing and strengthening triboeffect are formulated. Structural condition characteristics for the surface layers of copper alloys during friction on steel in the mode of boundary lubrication in surface-active lubricants, are described. The conditions for achieving minimum power losses of such tribosystems for friction and wear have been found. The greatest service life of tribounit in a lubricating medium containing surfactants is resulted from wear resistance increase of a copper alloy with a relative decrease in hardness and increased plasticity of its surface layer. At the same time, a decrease in hardness due to the plasticizing effect of surfactants occurs only in the near-surface deformed layer of tribomaterial, while in its deeper layers with no plasticization resulted from a lubricating medium effect, the mechanical characteristics of the antifriction alloy remain at the required high level. It is demonstrated that alloys with a single-phase structure of an α-solid solution and a wide concentration range of solubility of the alloying element in the solid state meet these requirements. It is found that such boundary conditions are provided by the presence of stationary macroscopic diffusion flows of alloying elements in the zone of contact deformation of a polycomponent tribomaterial. The role of local diffusion phenomena in quasispinodal phase transitions is indicated. Examples of the selective transfer phenomenon during friction in industrial lubricants, are given.

Improving the Fracture Toughness of Boron Carbide via Minor Additions of SiC and TiB2 Through Hot-Press Sintering.

Boron carbide (B4C) is an essential material in various high-performance applications due to its light weight and hardness. In this work, B4C-based composites were fabricated via a powder route consisting of powder mixing, precursor preparation, and hot-pressing under vacuum. The composites' mechanical properties and microstructure were analyzed to investigate the effect of adding minor second-phase particles. In addition to homogenizing the grain size, the addition of SiC (≤10 wt%) to B4C increased its strength and improved its fracture toughness, with values reaching 551 MPa and 3.22 MPa m1/2, respectively. Meanwhile, the addition of TiB2 (≤10 wt%) significantly improved the strength and fracture toughness only, with values reaching 548 MPa and 3.92 MPa m1/2, respectively, with only a minimal decrease in hardness. Microstructural analysis revealed that the second-phase particles were uniformly distributed and reduced the average grain size, contributing to the increase in strength. Additionally, the TiB2 particles impeded crack propagation and induced crack deflection at the interface, indicating the formation of an intergranular fracture mode. On the contrary, the addition of SiC primarily resulted in transgranular fracture behavior, though it still improved the toughness of the B4C. These results suggest that small amounts of SiC and TiB2 can effectively enhance the mechanical properties of B4C ceramics while maintaining the lightweight characteristics critical for military and aerospace applications.

Nanoindentation mechanical studies of bulk AlN single crystals with different orientations

Abstract This study utilized nanoindentation to perform nano-mechanical tests on freestanding aluminum nitride (AlN) single crystal substrates with (0002), (10–10), and (11–20) orientations prepared by the physical vapor transport (PVT) method with varying indentation depths. The results indicate that the c-plane exhibits greater hardness and smaller Young’s modulus compared to other orientations. Moreover, the mechanical properties of AlN with different orientations demonstrate consistency with the indentation size effect, showing a decrease in both hardness and Young’s modulus with increasing indentation depth. Surface morphology of the indentations was observed using SEM, revealing that at high loads, no obvious cracks were found in the c-plane indentation except for slight deformation, while the m-plane and a-plane indentations produced cracks extending along the a- and m-directions, respectively. Cathodoluminescence (CL) results demonstrated that dislocations and structural defects generated by the indentation produced the luminescence quenching. Notably, the inverted triangular dislocation slip region was clearly observed in the panchromatic CL images of c-plane indentation. The anisotropy of the phonon peaks at different crystal planes and the nature of the local stress at the indentation were further analyzed using Raman spectroscopy.

Effect of interstitial nitrogen on physical and mechanical properties of Al0.5CoCrNi high-entropy alloys: a first-principles study

Abstract The N-doped high entropy alloys (HEAs) have recently garnered significant interest for their outstanding mechanical properties, making them valuable structural materials within the industry, aerospace, and biomedical science. In this work, the impact of interstitial N atom on various properties of Al0.5CoCrNi HEA is investigated through first-principle calculations. Specifically, the changes in lattice constant, formation energy, elastic modulus, density of states, Vickers hardness, Debye temperature, energy factor, and charge density caused by the presence of interstitial N atom are analyzed. The results show that the interstitial N atoms lead to a decrease of the sample stability due to an increasing formation energy of the N-doped HEA. As the interstitial N content increases, the elastic module decreases, and an apparent anisotropy appears in N-doped HEA. Moreover, Vickers hardness decreases, suggesting the change of the stiffness and deformation characteristics. Compared to the N-doped tetrahedrons, the N-doped octahedrons exhibit high ductility due to an increasing Poisson’s ratio, a decreasing G/B ratio, and an increasing Cauchy pressure. The significant decreasing Debye temperature and average sound velocity reduces the thermal stability. The change of the electronic structure suggests the possibility for customizing electronic and optical properties. Additionally, the low energy factors for screw and edge dislocations promote dislocation nucleation in N-doped HEA. Charge density analysis reveals strong bonding characteristics, potentially affecting the chemical stability and reactivity. This work provides a unique perspective on the N-doped mechanical mechanism, and offers important insights for the advancement of advanced N-doped HEA.

Layer thickness dependent interface strengthening of nanolayered W/NbMoTaW medium-entropy alloys

In this work, the interface strengthening behavior of nanostructural W/NbMoTaW medium-entropy multilayer films with different W layer thicknesses was studied by a nanoindentation test. Results indicated that the hardness of multilayer films presented a significant size-dependent effect with the decrease of W layer thickness. The multilayer film reached a peak hardness of 19.8 GPa on account of interface strengthening at the critical layer thickness of 10 nm. An amorphous NbMoTaW layer leads to a decrease in hardness of multilayer films when W layer thickness was less than 10 nm. The room temperature toughness of the multilayer films predicted by the hardness/modulus ratio was improved with the decrease of W layer thickness. The size-dependent interface strengthening due to the decreasing W layer thickness and the solid solution strengthening due to the severe lattice distortion of the NbMoTaW layer are the main strengthening mechanisms of the multilayers.

Comprehensive impact of pre-treatment methods on white radish quality, water migration, and microstructure

The preprocessing stage is crucial in vegetable processing, significantly influencing the final product's quality. This study investigates the effects of various pre-pre-treatment methods, including cutting, blanching, osmotic, and ultrasound-assisted osmotic treatment, on the quality characteristics, water migration, and microstructure of white radish. The results showed that osmosis and ultrasound-assisted osmosis has the least effect on the total color difference (ΔE) and the greatest water loss (WL) (p < 0.05); blanching has the least effect on the hardness and eutectic points (p < 0.05); and the blanching-ultrasound-assisted osmosis has the greatest solid gain (p < 0.05). The increase of WL led to a decrease in hardness (−0.82). By analyzing the quality characteristics of different pre-treatment methods, contributing to the development of suitable pre-treatment methods for different products and optimization pre-treatments according to requirements. The mechanism of quality characteristics of pre-treatments on products is the future research direction.

Melatonin maintains the quality and cell wall structure of plum fruits under low temperature storage

To enhance the quality of plum fruits under low temperature storage, the impact of melatonin (MT) treatment (100 μmol L−1) on the quality and cell wall structure of plum fruits under low temperature storage (at 4 °C for 28 days) was examined. The results showed that the contents of total soluble solids, total sugar, titratable acid, and vitamin C in plum fruits treated with MT were higher than control under low temperature storage, and MT helped to prevent pulp browning and maintained the overall quality of the fruits. In addition, MT inhibited the conversion of ion-binding pectin and covalently-bound pectin of plum fruits into water-soluble pectin under low temperature storage. It also decreased the activities of pectin methylesterase, polygalacturonase, β-galactosidase, and endo-β-1, 4-glucanase, while increasing the activities of xyloglucan endotransglycosylase/hydrolase and α-l-arabinofuranosidase. Correlation analysis showed that the fruit hardness and pulp hardness were positively correlated with the covalently-bound pectin content, hemicellulose content, and cellulose content, and negatively correlated with the water-soluble pectin content, ion-binding pectin content, pectin methylesterase activity, β-galactosidase activity, and endo-β-1, 4-glucanase activity. Moreover, the cell structure of plum fruits treated with MT remained more intact and tightly arranged under low temperature storage, with slower degradation of the middle lamella and higher cell wall thickness. This was beneficial for maintaining the integrity of the cell wall structure and inhibiting the increase of intercellular spaces. In conclusion, MT can maintain the quality and cell wall structure of plum fruits, inhibit cell wall degradation, and slow down the decrease in fruit hardness under low temperature storage.

Urushiol-Based Coating with High Surface Hydrophilicity for Easy-Cleaning of Oil Pollutants.

Urushiol is recognized as a sustainable coating material with superior properties; however, it faces significant challenges in applications such as petrochemicals and marine engineering due to surface oil contamination. This study aimed to enhance the cleanability of urushiol-based coatings through hydrophilic modification. Polyethylene glycol monooleate (PEGMO) was identified as an appropriate hydrophilic macromonomer and utilized as a modifier to develop a novel urushiol-based coating, termed P(U-PEGMO), via thermal curing. The results indicated that copolymerization occurred between urushiol and PEGMO during the curing process, forming a stable urushiol copolymer with favorable compatibility. The incorporation of PEGMO greatly improved the surface hydrophilicity of the coatings, as evidenced by a reduction in the water contact angle to below 30° when the modifier content reached 30% or higher, demonstrating a high degree of surface hydrophilicity. This enhanced property imparted the modified coating with underwater superoleophobicity and reduced oil adhesion, thereby facilitating the removal of oil. The cleaning performance was evaluated using a simple water rinsing method, after which, less than 2.5 wt% of oil residues remained on the surface of the modified coating. The high hydrophilicity is considered responsible for the coating's easy-cleaning capability. In addition, the modified coatings exhibited improved flexibility and impact resistance, albeit with a slight decrease in hardness.

Improvement of overall quality of black rice by stabilization combined with solid-state fermentation

The application of black rice in food industry is challenging due to its short shelf life, poor cooking and eating quality. Superheated steam (SS) and far infrared radiation (FIR) are effective ways of stabilization and might be beneficial to solid-state fermentation (SSF). Therefore, stabilization treatments (SS and FIR) combined with SSF by Aspergillus oryzae were applied to furtherly improve the overall quality of black rice in present study. Results indicated that combined treatments were more favorable to shorten cooking time, increase water absorption and solid loss, resulting improvement of cooking quality of black rice. Besides, the significant decrease in hardness and chewiness after combined treatments was also good for the texture improvement. Moreover, black rice after combined treatments showed significantly higher contents of free phenolics, flavonoids, antioxidant activities, and phenolic acids, while their contents in bound form were significantly decreased, leading to significant increase of nutritional properties. Furthermore, black rice after combined treatments had significantly lower acid value and peroxide value during accelerated storage. Particularly, far infrared radiation combined with SSF was the most valued to improve the overall quality of black rice. These improvements were mainly ascribed to the enhancement of hydrolase activities based on the synergistic effect between stabilization treatments and SSF, which led to more significant pasting viscosities decrease, crystal structure destruction, cell wall rupture and starch degradation. The above results will provide a favorable strategy to improve the overall quality of black rice and then promote its consumption and application in food industry. Industrial relevanceThe short shelf life, poor cooking and eating quality severely limit the utilities of black rice in food industry. Heat processing is one of the most efficient strategies used in food industry to improve quality and prolong shelf life. Superheated steam and far infrared radiation are typical innovative heating technologies, and they are more energy efficient and more effective than conventional heating methods. In our previous work, they were effective ways of stabilization to extend the shelf life of black rice, and the starch after above treatments was partially gelatinized, which might be beneficial to the solid-state fermentation and thereby furtherly improve the overall quality of black rice. The present study aims to provide a favorable strategy to improve the overall quality of black rice and then promote its consumption and application in food industry.

Enhancing thermal stability of laser powder bed fusion fabricated 60NiTi alloy via Nb alloying

60NiTi (Ni55Ti45) alloy has a unique microstructure composed of a B2 NiTi matrix with supersaturated Ni atoms and numerous nanoscale Ni4Ti3 precipitates, resulting in excellent strength, hardness, and superelasticity. However, these characteristics make it challenging to directly form complex components. In addition, significant decrease in Ni saturation degree and coarsening of Ni4Ti3 precipitates lead to performance degradation of 60NiTi alloy during prolonged service. In this study, a 60NiTi-Nb (Ni55Ti40Nb5) alloy was successfully designed and fabricated using Laser Powder Bed Fusion (LPBF), which exhibits complex geometry and superior thermal stability. Particularly, after a heat-treatment at 500 °C for 5 h, the size of precipitates Ni4Ti3 in the Ni55Ti40Nb5 alloy increases by just over 10 nm, maintaining a hardness above 620 HV, whereas the Ni55Ti45 alloy experiences a precipitate size increase close to 200 nm, leading to a hardness decrease of 100 HV. The superior thermal stability is primarily attributed to the enrichment of Nb surrounding the Ni4Ti3 precipitates, which reduces the growth rate of the Ni4Ti3 precipitates, and the coexistence of spinodal decomposition and ordering in the matrix, thus enhancing microstructural stability. This study provides valuable insights for the development of 60NiTi complex structural components with high thermal stability, thereby promoting the application of 60NiTi alloys.

Study on the painting methods, amount and thermal properties of waterborne acrylic paint on bamboo-laminated lumber for furniture

In order to understand the finishing effect of Waterborne Acrylic Paint under different painting methods and amount, bamboo-laminated lumber for furniture was coated with waterborne acrylic paint, then the effects of different painting methods and amount on the drying rate, smoothness, hardness, adhesion and wear resistance of the paint film were investigated. Further, the mechanism of film formation was described by thermal property analysis using thermogravimetry and differential scanning calorimeter. The results show that different painting methods have little effect on film properties, the drying time of primer and topcoat are not affected by them, which is 8/8.5 min for primer surface/solid and 6.5/7 min for topcoats. The film surface hardness and adhesion can reach B and 0 grade, the best wear resistance of the film is 51.24 mg·100 r−1 when using one-layer primer one-layer topcoat. Different coating amount has great influence on film properties, the drying speed of the film increases with the increase of the painting amount. The film properties reach the best when the painting amount is 80 g/m2, while too little painting amount leads to the decrease of hardness, and too much leads to the wear resistance weaken. Thermal analysis of the primer and topcoat show that water decomposition occurs at 100 ℃ and thermal decomposition of organic components occur at 350 ℃. Topcoats have better thermal stability than primers higher than that of topcoat, the topcoat displayed better thermal stability than the primer.

Investigation of ion irradiation effects on mineral analogues of concrete aggregates

Irradiation can cause prominent damage to reactor concrete aggregates leading to amorphization, strength and modulus decrease, radiation induced volume expansion (RIVE) and micro-cracking, which limits their long-term performance. To develop an improved understanding of irradiation effects in concrete, three mineral analogues of concrete aggregates (limestone, marble and quartzite) were irradiated by 5.5 MeV He ions and 13 MeV Ni ions to surface doses of 0.011 displacements per atom (dpa) and 0.23 dpa, respectively, at room temperature. The two different ion species allow irradiation spectrum effects (ionizing and displacive) to be examined. Irradiation induced cracks were observed in He irradiated limestone and marble, and Ni irradiated quartzite. Full amorphization was observed in Ni irradiated quartzite with 14.3 % RIVE, and ∼25 % hardness and modulus decrease, while almost no change was observed in He irradiated quartzite except 4.35 % RIVE, revealing a possible ionization enhanced diffusion effect for high energy light ions. Furthermore, partial amorphization was observed in Ni irradiated marble and limestone matrix with a 12 % hardness decrease in marble while no amorphization was observed for He irradiation with a 20 % hardness increase in limestone matrix. The role of knock-on damage and irradiation spectrum on amorphization, volumetric expansion and mechanical property changes are discussed. Moreover, the onset and critical doses for amorphization and RIVE in quartz are obtained for ion irradiations at room temperature. The dose dependence of RIVE exhibits a delay compared to the amorphization behavior. The superior irradiation resistance of calcite phase compared to quartz phase implies there could be advantages to using calcareous aggregates and lowering the usage of siliceous aggregates for concrete in nuclear power plants for extended operation beyond 60 years. However, other effects such as corrosion, aging and reactions during severe accidents should also be considered, and further investigations are needed.

Physical properties and thermal stability of zirconium platinum nitride thin films

Ternary transition metal nitrides (TMNs) promise to significantly expand the material design space by opening new functionality and enhancing existing properties. However, most systems have only been investigated computationally, and limited understanding of their stabilizing mechanisms restricts translation to experimental synthesis. To better elucidate key factors in designing ternary TMNs, we experimentally fabricate and analyze the physical properties of the ternary Zr–Pt–N system. Structural analysis and density functional theory modeling demonstrate that Pt substitutes nitrogen on the nonmetallic sublattice, which destabilizes the rock salt structure and forms a complex cubic phase. We also show insolubility of Pt in the Zr–Pt–N at 45 at. % with the formation of a secondary Pt-rich phase. The measured reduced plasma frequency, decrease in resistivity, and decrease in hardness reflect a dominance of metallic behavior in bonding. Additionally, we observe the exsolution of Pt nano precipitates from the Zr–Pt–N films upon annealing as well as degradation in the nitridic film's thermal stability. Even at low concentrations (1%), Pt facilitates a solid reaction with the Si substrate that is otherwise inaccessible in ZrN films.

Study on the Microstructural and Proficiencies of Heat‐Affected Zone in High‐Slope Mountainous Welded Pipeline Steels

The failure rate of pipelines in mountainous areas is much higher than that in other service areas. To ensure the efficiency and quality of the project, automatic welding has become a development trend. The heat‐affected zone (HAZ) as a weak area, to a large extent, reflects the quality of welded joints. Herein, the microstructure and mechanical properties of HAZ on both sides of welded joints under a 30° large slope are characterized by high‐resolution transmission electron microscopy, electron backscattered diffraction, and Charpy impact. The results show that the properties of HAZ are affected by many strengthening mechanisms such as grain refinement, solid solution, dislocation, and precipitation, among which grain refinement plays a leading role. The slope will affect the NbC phase size and grain size, resulting in differences in HAZ properties on both sides. The grain size of each microzone in the lower side HAZ is coarsened compared to the higher side, and the dislocation density is lower, leading to a decrease in hardness and impact toughness, thus becoming the weakest region in the welded joint. Therefore, for welding under the condition of slope, attention must be paid to the influence of slope on the performance of welded joints.