Increasing Aging Time Research Articles

Influences of deformation defects on etching behaviors of high-strength and high-conductivity Cu alloy for lead frame

With increasing integration of the semiconductor devices, the requirements on size accuracy and surface quality of the lead frame are higher. Cold-rolling and low-temperature aging are usually used in processing of the Cu alloy for lead frame, which generate/eliminate the deformation defects that affect the etched surface morphology and roughness, while the influence mechanisms have not been well revealed. In this study, the CuCrSn alloy was used as the experimental material, which was cold-rolled to different degree and then aged at 450 °C for different time, and the microstructures and etched surfaces of the specimens were characterized. The results show that etched surface morphologies of grains with different orientations in the coarse-grained Cu alloy are different. With increasing cold-rolling deformation, the influences of grain orientation become less obvious, and the dislocation groups on the slip planes result in grooves approximately parallel to the rolling direction, meanwhile the surface uniformity are improved and the surface roughness decreases. For the 80 % cold-rolled Cu alloy, the density of grooves decreases with increasing aging time and elimination of the dislocations, and the etched surface roughness decreases firstly and then tends to be stable. The etched surface changes significantly and the surface roughness increase obviously after recrystallization of the specimen.

Effect of hygrothermal aging on mechanical properties of continuous flax fiber composites

AbstractThe influence of hygrothermal aging on the mechanical properties of flax fiber‐reinforced polymer (FFRP) composites was studied by examining the mechanical properties and failure mechanism of the composite laminates exposed in distilled water at different temperatures. The resin transfer molding (RTM) process was used to manufacture FFRP laminates, which were then subjected to accelerated aging tests in distilled water at different temperatures. The moisture absorption characteristics of FFRP were analyzed by a water absorption test. Tensile, bending, and low‐velocity impact tests of laminates after different aging conditions were performed. Combined with DSC and FTIR tests, the failure mechanism of FFRP exposure to hygrothermal aging was analyzed. The result indicated that the increase in temperature will accelerate the moisture absorption process of FFRP, and the hygroscopic behaviors at different temperatures conform to Fick's law. In the early stage of hygrothermal aging, the composites undergo post‐curing, and the tensile and bending strengths increase. After that, the tensile and bending strengths are decreased because of the thermo‐oxygen aging of materials and fiber/matrix interface damage. After hygrothermal aging, the impact peak force of FFRP decreases obviously while the absorbed energy increases due to the increase of internal defects and plasticization of composites. The increase of hygrothermal aging temperature aggravates the aging of materials, resulting in a more obvious decline in the tensile, bending, and impact properties of the composites.Highlights The effect of hygrothermal aging on the mechanical properties of FFRP is investigated. With the increase of hygrothermal aging time, the tensile and bending strength of FFRP increased at the early stage of aging and then decreased. After hygrothermal aging, the impact peak force of FFRP decreases and the absorbed energy increases due to the increase of internal defects and plasticization of composites.

Effects of aging heat treatment on the mechanical properties of NiTi triply periodic minimal surface

This study investigated the impact of aging heat treatment time on the mechanical properties of NiTi triply periodic minimal surface structures fabricated through laser powder bed fusion. X-ray diffraction analysis results indicate that with increasing aging time, the NiTi2 phase precipitates while the content of the B19’ phase decreases. At 10 h of aging time, the Ni4Ti3 phase becomes evident in the sample. The differential scanning calorimeter results show that R phase transformation occurs, and the phase transformation temperature increases when the aging time reaches 6 h. Microhardness increases with aging time, peaking at 477.8 HV after 10 h. Compression experiment results reveal a maximum elastic modulus of 1262.82 MPa for the gyroid sheet-shaped structure achieved after 2 h. In addition, the superelasticity test indicates the highest recoverable strains at 2%, 4%, and 6% compressive strain for the gyroid rod-shaped structure after aging for 10 h. In cyclic compression experiments, the ratio of shape memory recovery increases from 40% at 0 h to 97% at 6 h. Fracture analysis results show that the transition in the fracture mechanism from brittle fracture to quasi-cleavage fracture occurs after aging heat treatment.

Aging Treatment Induces the Preferential Crystallographic Orientation of αs in the Near-α Titanium Alloy Ti60

In this article, we subjected the Ti60 alloy to solid-solution treatment at 1020 °C and aging treatment at 600 °C, respectively, achieving a bimodal microstructure. The microstructures obtained after aging treatment showed no significant difference in the primary α-phase content, size, and width of the lamellar α phase. This suggests that the final microstructure morphology is primarily determined by the solid-solution temperature, with the aging process exerting less pronounced effects on microstructural alterations. Furthermore, we investigated the effect of solid-solution and aging treatment on the crystallographic orientation evolution of the secondary α phase (αs) in the near-α titanium alloy Ti60. The αs phase displays a random orientation in solid-solution treatment sample, while it demonstrated a preferential {0 1 −1 0} orientation after aging treatment. This interesting phenomenon is attributed to the enhanced variant selection resulting from the dissolution of variant near 60° and 90° during aging. Furthermore, the αs with {0 1 −1 0} orientation nucleated at the grain boundary and coalesced into larger αs lath with increasing aging time, further contributing to the αs {0 1 −1 0} texture.

Research on the Thermal Aging Characteristics of Crosslinked Polyethylene Cables Based on Polarization and Depolarization Current Measurement

Although XLPE cables are widely used in power transmission and distribution systems, their insulating properties are susceptible to degradation due to thermal aging. In order to clarify the influence law of the thermal aging process on the structural and dielectric properties of XLPE cables, this paper investigates the thermal aging characteristics of XLPE cables by using polarization and depolarization current measurement. Results show that when the XLPE cable is aged at 140 °C, the crystallinity of the insulation layer appears to increase and then decrease. With the increase in aging time, micron-sized microvoids appear on the surface of the XLPE. At the same time, the DC conductivity and 0.1 Hz dielectric loss factor of the insulating layer increase with the aging time. The average DC conductivity increased from 2.26 × 10−16 S/m for new cables to 4.47 × 10−16 S/m after aging for 432 h, while the dielectric loss increased from 0.11% to 0.42%. The polarization characteristics of thermal-aged cables were further analyzed using the extended Debye model. Results indicate that the time constant of the third branch of the model increased significantly with increasing aging time. A correspondence between this parameter and the thermal aging time of the cable was established. Thermal aging can damage the crystalline structure of XLPE, so that the number of interfaces between the crystalline and amorphous regions of the material increases, resulting in structural damages and a decline in the dielectric properties of the cable insulation.

Evolution of aging depth gradient distribution in SBS-modified bitumen during the aging of field

This study investigated the distribution of aging depth gradients in styrene-butadiene-styrene modified bitumen (SBSMB) during natural aging. SBSMB was sourced from bitumen recycling tests and was stratified into upper, middle, and lower layers according to depth. To examine the effects of various aging depths, SBSMB samples from different depths were prepared for subsequent bitumen recycling tests. Then, studying the rheological performance of the SBSMB involved conducting multiple stress creep recovery tests. Subsequently, investigating the bee structure and nanoscale indicators of SBSMB at various aging depths involved utilizing atomic force microscopy testing. Finally, the Verhulst model was applied to assess the aging of SBSMB at different depths. The results have shown that natural aging has gradually diffused from the surface to the interior of the bitumen. An increase in aging time leads to a more pronounced aging effect at the upper levels and an accelerated the downward diffusion rate. This ultimately results in a gradient behavior of the rheological properties of SBSMB at different depths. The quantity of bee structures and the distribution density of bee structures in SBSMB both progressively decrease with increased aging depth. As aging time increases, the aging properties of SBSMB exhibit significant gradient behavior at different depths. Simultaneously, the Verhulst model accurately explain the aging trend of bitumen at different nanoscale depths.

Effects of aging on the bioactive flavonoids and fungal diversity of Pericarpium Citri Reticulatae (Citrus reticulata ‘Chachi’)

Samples of Pericarpium Citri Reticulatae (Citrus reticulata 'Chachi', CP-‘Chachi’), which collected in December of 2017, 2013, 2003 and 1993 with the natural aging process for 5, 10, 20 and 30 years, were used to compared the changes in total polyphenols, total flavonoids and fungal community composition. The relationship among these factors was analyzed. The content of flavonoids in CP-‘Chachi’ was qualitatively and quantitatively determined by HPLC system. ITS (Internal Transcribed spacer) sequencing techniques were used to detect the changes of microbial communities during the aging process of CP-‘Chachi’. The results indicated that the levels of flavonoids and total polyphenols, except for hesperidin, increased aging time, with the most significant growth observed in 5-O-desmethyl nobiletin at 298.36%, while hesperidin decreased by 32.52%. The three most abundant genera were Xeromyces, Symmetrospora and Cladosporium, and the highest number of genera was found in CP-2013. The community composition of CP-1993 and CP-2003 was highly similar, Xeromyces accounted for 84.04% and 83.58% in CP-1993 and CP-2003, respectively. The findings demonstrated that only the abundance of Xeromyces was positively correlated with the accumulation of active components during the aging process of CP-‘Chachi’. This indicated that Xeromyces was considered the dominant genus responsible for the aging quality of CP-'Chachi'. The relationship between the changes in flavonoids and fungal diveresity was preliminarily verified, which provided new insights into the study of the aging mechanism of CP-‘Chachi’ and its influencing factors on quality.

Effect of Si3N4 nanoparticles on IMC as well as mechanical properties of Sn58Bi/Cu solder joints during thermal aging

This paper investigated the changes in microstructure, intermetallic compounds (IMC), and mechanical properties of Sn58Bi/Cu and Sn58Bi-0.6 Si3N4/Cu solder joints in the thermal aging process at 125 °C. With the increase of the thermal aging time, the Bi-phase was gradually coarsened, but the coarsening of the Bi-phase was suppressed after adding Si3N4 NPs. The thickness of the IMC increased continuously, and some areas even detached into the solder matrix, accompanied by gradual grain growth. For the samples with Si3N4 NPs, the IMC thickness significantly decreased, and the grain size was finer. Fractures mainly occur in the Bi-rich phase of the solder matrix following a brief period of thermal aging. However, as the aging time increases, the fracture location gradually shifts from the solder matrix to the IMC, resulting in intergranular and transgranular fractures. However, the shear strength of solder joints with added Si3N4 NPs was higher during the same aging period.

Electrochemical characteristic and microstructure of Ti-6Al-7Nb alloy by centrifugal casting for orthopedic implant based on ageing time variations

The alternative Ti-6Al-7Nb alloy has gained extensive progression due to its ability to eliminate the cytotoxicity of vanadium (V) in Ti-6Al-4V alloy for orthopedic implants. The production of titanium alloys by centrifugal casting shows significant potential to reduce costs. Heat treatment and aging can tailor the microstructure and improve the corrosion resistance of titanium alloys. This study examines the effects of various ageing times on the microstructure and corrosion resistance of a centrifugal cast Ti-6Al-7Nb alloy that has previously been heated and treated at a temperature of 1050 °C, and subsequently cooled to room temperature in argon atmosphere gas. Ageing was carried out at a temperature of 550 °C with variable times of 0, 4, 6, and 8 hours. The surface morphology, metal phase changes, and electrochemical characterization were tested using an optical microscope (OM), X-ray diffraction (XRD), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The basket-weave microstructure is formed where globularization occurs in some phases as ageing time increases. Increasing the FWHM α value is correlated with increasing the amount of α' martensite phase. As an ageing time enhances, the temperature might offer a greater driving constrain for the nucleation and expansion of the lamellar phase (α). Ageing of 8 hours has the lowest corrosion rate, 0.0023 mpy and highest corrosion resistance, 90457 Ω∙cm2, due to the partially bimodal structure and grain refinement with a smallest grain size of 327.87 µm. Tafel polarization results show that all passivated samples are stable in the Solution Body Fluid (SBF). This work can be used as a starting point for developing microstructural evolution in titanium alloys

Thermal Oxidative Aging and Service Life Prediction of Commercial Ethylene-Propylene-Diene Monomer Spacer Damping Composites for High-Voltage Transmission Lines.

The aging behavior and life prediction of rubber composites are crucial for ensuring high-voltage transmission line safety. In this study, commercially available ethylene-propylene-diene monomer (EPDM) spacer composites were chosen and investigated to elucidate the structure and performance changes under various aging conditions. The results showed an increased C=O peak intensity with increasing aging time, suggesting intensified oxidation of ethylene and propylene units. Furthermore, the surface morphology of commercial EPDM composites displayed increased roughness and aggregation after aging. Furthermore, hardness, modulus at 100% elongation, and tensile strength of commercial EPDM composites exhibited a general increase, while elongation at break decreased. Additionally, the damping performance decreased significantly after aging, with a 20.6% reduction in loss factor (20 °C) after aging at 100 °C for 672 h. With increasing aging time and temperature, the compression set gradually rose due to the irreversible movement of the rubber chains under stress. A life prediction model was developed based on a compression set to estimate the lifetime of rubber composites for spacer bars. The results showed that the product's life was 8.4 years at 20 °C. Therefore, the establishment of a life prediction model for rubber composites can provide valuable technical support for spacer product services.

Effect of water immersion on shear strength of epoxy adhesive filled with graphene nanoplatelets

Abstract Adhesive bonds are frequently used in industries such as aerospace, automotive, and civil engineering due to their ability to reduce damage to the adherend and their lightweight. However, their application is restricted by their inadequate durability and reliability in hostile environments. Graphene nanoplatelets (GNPs) are employed to enhance epoxy adhesives in this article. The thick adherend shear test is utilized to examine how the shear properties change with different water ageing times. Before exposure to water ageing conditions, GNP-reinforced adhesives exhibit a 3.51% increase compared with neat epoxy at a GNP content of 0.25 wt%. However, after 56 days of water ageing, the increase in shear strength is found to be 13.79%. This suggests that the well-dispersed GNP can reduce the degradation rate in shear properties by half, from 16.71 to 8.44%, at a GNP content of 0.25 wt%. Additionally, as water ageing time increases, the positive influence of GNP on shear properties becomes more evident. The addition of GNP delays the degradation of shear properties caused by water ageing conditions. The effect of GNP does not improve with higher GNP content. When the GNP contents increase to 1 wt%, the shear strength of the GNP-reinforced adhesive decreases compared to neat epoxy.

Investigation of the ageing-induced R-phase and its impact on static/cyclic tensile failure in Ni50.9Ti49.1 wire

The trade-off between the safety and effectiveness of NiTi wire in practical applications has consistently hindered its advancement. This underscores the significance of adjusting its microstructure via appropriate heat-treatment techniques. This study systematically investigates the evolution of the constitution phases of the matrix and the grain size as the aging time increases from 3 min to 3 h at 550 °C for Ni50.9Ti49.1 wire, and highlights the significant role of the R phase in static/cyclic tensile failure behavior. When aged for 30 min, the matrix consists mainly of the B2 phase, similar to the as-received wire, while it tends to transform into the R phase during loading (intermediate-R phase). In contrast, aging for 3 h leads to the formation of the R phase as the matrix phase (matrix-R phase). The two types of R phase are discussed and compared in detail with regard to their contribution to the static/cyclic tensile failure behaviour. The longest fatigue life was obtained in wires with the R phase as the matrix phase, which was due to the combined effect: (i) the rapid attainment of a stable state so as to minimise the extent of phase transformation; (ii) coordination deformation of twin and dislocation to alleviate stress concentration; (iii) and the strong bonding between Ti2Ni and the matrix that reduces the occurrence of the “stretching into the hole-coalescence-microcrack process”. The enhanced flexibility observed in the wire with matrix-R phase is due to its reduced elastic modulus and lower transformation plateau. The increase in plasticity is linked to changes in the wire's fracture behavior resulting from grain growth. Such microstructural changes allow the alloy wire to exhibit a more uniform plastic deformation under stress, which in turn postpones the onset of significant fracturing.

Microstructural evaluation of interfacial intermetallic compounds between Sn58Bi and ENEPIG

BackgroundLow carbonization and Restriction of Hazardous Substances (RoHS) regulations have promoted the development of low-temperature lead-free solder. The solder and substrate are critical entities of joint connections. MethodsSn58Bi has been considered a promising low-temperature solder. Electroless nickel/electroless palladium/immersion gold (ENEPIG) is a good surface finish that prevents solder joints from oxidizing and extends the shelf life of the substrates. In this study, the interfacial reactions between the Sn58Bi solder and ENEPIG surface finish were systematically analyzed. Findings(Au,Pd,Ni)(Sn,Bi)4 was observed after reflow at 160 °C. Au and Pd dissolved into solder rapidly in the beginning. NiSn4 and Ni3Sn4 with small amounts of Au and Pd dissolution formed at the interface after aging. The morphology of NiSn4 evolved from block-like to needle-shaped and finally to a layered configuration as the aging temperature and time increase. Ni3Sn4 was observed between NiSn4 and substrate above 100 °C. This study established the growth mechanism of intermetallic compounds (IMCs) in the reaction between Sn58Bi and ENEPIG for low-carbon emitting processes.

Precipitate evolution and mechanical properties of Si-modified A286 alloy aged at 510 °C

Si-modified A286 alloy was designed to be compatible with liquid lead-bismuth eutectic (LBE) metal. The addition of Si resulted in a distinct microstructure compared to A286 alloy. In this study, we investigated the microstructure and mechanical properties of the experimental alloy after 510 °C isothermal aging for 5000 h. The results showed the presence of two types of G-phase in the alloy before aging: one with a core-shell morphology, the other with a chain-like morphology. After long-term aging, the Si-modified A286 alloy maintained the same refined grains as in the SAT(solid solution and aging treatment) specimen, with minimal changes observed in the two G-phases even after 5000 h of aging. However, a newly precipitated submicron spherical-like G-phase was observed on the grain boundaries after 500 h of aging, leading to a significant decrease in impact toughness. These spherical-like G-phases gradually coarsened with increasing aging time and eventually stabilized after 2000 h. The reduction in impact toughness in the Si-modified A286 alloy was attributed to the precipitation of the spherical-like G-phase.

Effect of ultrasonic processing on beef tenderness in longissimus lumborum during aging by proteomics analysis

This investigation was aimed to evaluate the proteins related to beef tenderness at different aging times (1, 3, 7 d) and to explain the changes in the longissimus lumborum at the molecular level with ultrasound treatment. The pH value decreased significantly (p<0.05) with increasing aging time, and was lower in the ultrasonic group compared to the non-ultrasonic group. It indicated that ultrasound had a positive effect on tenderness by maintaining lower cooking loss, higher water-holding capacity (WHC), and higher myofibril fragmentation index (MFI), as demonstrated by the immunoblotting analysis of desmin and caspase-3. Twenty-eight proteins were identified as potential markers of tenderness. A PCA analysis confirmed the differential expression of tenderness-related proteins. Bioinformatics analysis suggested that these proteins, which were distributed in the cytoplasm, membrane, and mitochondria, were more likely to be impacted by ultrasound. Overall, the identified proteomics database of beef serves as a valuable reference for using ultrasound to enhance meat quality and reduce aging duration.

Microstructural evolution and mechanical properties of the rapidly-solidified and hot-extruded 2196 Al-Li alloy

The microstructural evolution and mechanical properties of the 2196 Al-Li alloy prepared by the vacuum gas atomization, hot-isostatic-pressing (HIP) and hot-extrusion were investigated. The results show that prior particle boundaries (PPBs) exist in the microstructure of the HIPed alloy, and hot-extrusion effectively breaks PPBs to restrict the element micro-segregations. The as-extruded alloy exhibits fine grains, and bears higher solution treatment temperature due to the absence of low-melting-point micro-segregations. In the ageing process, the alloy hardness continues to rise, and reaches the peak value at 48 h. The precipitation sequence of the alloy is determined to be: supersaturated solid solution (SSS) → GP zone + fine T1 + δ′ → T1 + θ′ + δ′, where T1 phase dominates the whole ageing process. The diameter of the T1 platelets increases gradually with the increase of ageing time, meanwhile the T1 number density slightly drops in the over-aged alloy. The 3% pre-stretching promotes the nucleation of T1 phase, and the peak-ageing time is shortened to 28 h. Besides, no over-ageing phenomenon is observed in the pre-stretched samples. The Mg-Cu and non-Cu clusters formed on the dislocations accelerate the precipitation of T1 phase and prevent the nucleation of θ′ phase. The yield strength (YS) and ultimate tensile strength (UTS) of the T8 sample are 490 MPa and 515 MPa, respectively, which is notably higher than the T6 sample. The tensile strength of the present alloy is relatively higher than that of the Al-Li alloys with a comparable Li content.

Understanding and mitigating temperature-induced agglomeration in silica-based chemical mechanical planarization (CMP) slurry storage

This study explores the impact of temperature on silica particle agglomeration in Chemical Mechanical Planarization (CMP) slurries during storage. Slurries were stored at 15 °C, room temperature, and 45 °C, and analyzed. ATR-FTIR, RAMAN, SEM, zeta potential, and LPC were employed providing qualitative and quantitative data on slurry stability and agglomeration tendencies. Elevated temperature storage significantly increased agglomeration and large particle counts with particle counts value of ∼1.2×107 Part./ml, likely due to water molecule dehydration leading to destabilization. Low-temperature storage also induced agglomeration but to a lesser extent with particle counts the value of ∼4.0×106 Part./ml compared with the RT (∼2.0×106 Part./ml). Short-term storage yielded soft agglomerates with LPC of ∼(2.0–4.0)×106 Part./ml, while long-term high-temperature storage led to hard agglomerates with LPC of ∼3.0×107 Part./ml. The ATR-FTIR and Raman analysis indicate that the spectroscopic features of the original slurry exhibited changes upon variation of storage temperature from RT to 15 and 45 °C. The study also explored the reversibility of agglomeration post-treatment, indicating a potential mitigation pathway. The results demonstrated an inverse relationship between temperature and dissolved oxygen (DO) in silica slurries. For example. the curves depict a decrease in oxygen content from ∼10 ppm at RT to 7 ppm at 45 °C with increasing aging time. A mechanism outlining the temperature and aging-induced agglomeration was proposed, linking temperature fluctuations and thermodynamic aspects to colloidal stability. These findings offer a robust understanding of temperature-induced agglomeration in silica-based CMP slurry storage, paving the way for developing strategies to alleviate these issues and ensuring consistent CMP performance in semiconductor manufacturing.

Color Change of Laminate Veneer Restorations Applied to Bleached Teeth.

The aim of this study was to examine the color stability of laminate veneer restorations restored with CAD/CAM material applied to bleached teeth. In this study, 80 upper central teeth extracted because of periodontal, orthodontic or trauma problems were used. The teeth were embedded in acrylic blocks and divided into 8 groups (n=10). Groups A, B, C and D were bleached with vital bleaching agent before preparation, and teeth were prepared for laminate veneer restorations. Groups E, F, G and H were prepared without bleaching. Groups A and E were restored with A1 GC LiSi İnitial HT blocks, Groups B and F were restored with A1 GC LiSi İnitial LT blocks, Groups C and G were restored with A1 IPS Emax CAD HT blocks, Groups D and H were restored with A1 IPS Emax CAD LT blocks. All restorations were adhesively cemented and aged for 2 and 5 years with thermal cycle. Color measurements of the restorations at the beginning, after 2 and 5 years of aging were measured with a spectrophotometer. All bleached groups had more color changes than the unbleached groups. The least color change after 2 years of aging was observed in GC LiSi Initial LT (ΔE00=0.81) and IPS Emax CAD LT (ΔE00=0.81) materials which were used on unbleached teeth and the most color change was observed in GC Initial LiSi HT (ΔE00=0.93) and IPS Emax CAD HT material (ΔE00=0.92) which were used on bleached teeth. After 5 years of aging, the least color change was observed in IPS Emax CAD LT (ΔE00=0.83) and GC LiSi Initial LT material (ΔE00=0.84) which were used on unbleached and the highest color change was observed in GC Initial LiSi HT (ΔE00=0.96) and IPS Emax CAD HT material (ΔE00=0.94) which were used on bleached teeth. Bleaching and translucency affect the color stability. No difference was detected between the color changes of GC LiSi Initial and IPS Emax CAD materials. The increase in aging time increased the color changes of all materials. Bleaching and laminate veneer restorations may be preferred in many patients. For this reason, the long-term color change of laminate veneer restorations applied to bleached teeth is clinically very important. This study aimed to evaluate the effect of tooth bleaching on the long-term color change of laminate veneer restorations produced with different translucent CAD/CAM materials.

Precipitation behavior and electrical conductivity and mechanical properties of Cu-0.9Be-1.5Ni-0.04Y alloy

The optimum solid solution and aging processes for Cu-0.9Be-1.5Ni-0.04Y alloys, as well as the microstructure and strengthening mechanisms during aging were investigated. The results show that the optimum solid solution and aging temperatures are 980℃ and 480℃, respectively. During aging treatment at 480°C, the precipitation sequence of the Cu-0.9Be-1.5Ni-0.04Y alloy was supersaturated α solid solution → GP zone → γ″ phase → γ′ phase → γ phase. As increasing the aging time, the microhardness and yield strength of the alloy showed a trend of increasing and then decreasing, with the maximum of 220.9 HV and 626 MPa, respectively. The strengthening mechanisms of the nanoscale γ" and γ' phases in Cu-0.9Be-1.5Ni-0.04Y alloy were the shear mechanism and orowan mechanism, respectively. The electrical conductivity of the alloy increased and then remained more or less constant with increasing aging time, with a maximum of 39.78%IACS. The difference between the theoretical and measured values of the electrical conductivity of the alloy after aging at 480℃ for different times was less than 1%.

Effect of Methyl Hydro-Silicone Oil Content and Aging Time on Compression Modulus and Breakdown Strength of Additional Liquid Silicone Rubber Gel.

The performance of silicone rubber gel elastomers is affected by the composition and structure of the crosslinker. In this work, a two-component addition liquid silicone rubber gel material was developed, and the effects of the contents of two methyl hydro-silicone oils on the compression modulus and breakdown strength of the silicone rubber gel insulating material, as well as the performance change after hot air aging at different times (24 h, 48 h, 72 h, 96 h, 120 h, 144 h, 168 h), were studied. The results showed that the breakdown strength and compression modulus exhibited an upward trend with the increase in the hydrogen silicone oil content. The best performance was achieved in the silicone rubber gel with Si-H:Si-Vi = 1.4:1. Moreover, with the increase in aging time, the breakdown strength decreased and the compression modulus increased.