Effects of Al2O3-Particulate-Contained Composite Filler Materials on the Shear Strength of Alumina Joints

Al2O3l2O3 joints were brazed with a new kind of filler materials, which were formed by adding AI203 particulates into Ag-Cu-Ti active filler metal. The results showed that the material parameters (the Ti content, Al2O3 particulate volume fraction) of the composite filler materials affected the shear strength of brazed joints. When the Ti content was 2 wt pct in the filler metal, the shear strength of brazing joints decreased with the increasing the volume ratio of Al2O3 particulate. When the Ti content was 3 wt pct in the filler metal, the shear strength of joints increased from 93.75 MPa(AI203p 0 vol. pct) to 135.32 MPa(AI203p 15 vol. pct).

Theoretical study and numerical simulation of the stress fields of the Al_2O_3 joints brazed with composite filler materials

Non-linear finite element code MSC. Marc was utilized to analysis the field of stress of the Al2O3 joints brazed with composite filler materials. The properties of the filler materials were defined by using the mixing law, method of Mori-Tanaka and theory of Eshelby to ensure the accuracy and reliability of results of finite element method （FEM）. The results show stress in brazed beam is higher than that in base material. The maximal stress can be found in the interface of joint. And the experimental results show that the shear strength of joints increases from 93.75 MPa （ Al2O3p Ovol. % ） to 135.32 MPa （ Al2O3p 15vol. % ） when composition of titanium is 3wt% in the filler metal.

Effects of Al2O3 Particulates on the Thickness of Reaction Layer of Al2O3 Joints Brazed with Al2O3-Particulate-Contained Composite Filler Materials

In order to understand the rate-controlling process for the interfacial layer growth of brazing joints brazed with active composite filler materials, the thickness of brazing joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of AI2O3 participate was studied. The experimental results indicate although there are Al2O3 particulates added into active filler metals, the time dependence of interfacial layer growth is t2 as described by Fickian law for the joints brazed with conventional active filler metal. It also shows that the key factor affecting the interfacial layer growth is the volume fraction of alumina in the composite filler material compared with the titanium weight fraction in the filler material.

Application of Ag-Cu-Ti active metal composite filler in ceramic joining:a review

As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic materials,ceramics are often joined to metals and then used.Among the physical and chemical joining methods of ceramics to metals,the AMB method is efficient and simple,suitable for industrial applications,and has been a hot topic of research.However,due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing,composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure.This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining,with emphasis on the current stage of composite filler,and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.

Al2_3/Al2O3 Joint Brazed with Al2O3-particulate-contained Composite Ag-Cu-Ti Filler Material

Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy （SEM）, electron probe microscopy analysis （EPMA）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied. The experimental results indicated although there were Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal.

Effect of surface modification of ammonium polyphosphate-diatomite composite filler on the flame retardancy and smoke suppression of cellulose paper

Ammonium polyphosphate-diatomite composite filler(APP-diatomite composite filler)was modified with silane coupling agent KH550 to improve the flame retardancy of filled paper.Cone calorimeter was used to analyze the heat and smoke releasing rates,as well as smoke toxicity of the filled paper.The distribution of the composite filler particles in paper and the morphology of the charred residues after combustion were investigated by scanning electron microscope(SEM),and the chemical structure of the charred residues was studied with fourier transform infrared spectroscopy(FTIR).Results show that the peak heat releasing rate(PHRR),total heat release(THR)and peak mass loss rate(PMLR)of the filled paper with the modified APP-diatomite decreased markedly,compared with those for the control paper,while the charred residue after combustion increased.In addition,the filled paper had an increased peak rate of smoke release(RSR)and increased total smoke release(TSR)and peak CO production rates,but a decreased peak CO_(2) production rate.It was also found that part of the carbon element in the charred residue of the paper loaded with the modified APP-diatomite was in the forms of C=C=C,C≡C and C≡N,and the charred residue had a relatively more intact structure without apparent fiber breakage and longitudinal cracks.

Interaction between PCC Filler and Cellulosic Fiber in Fiber/Filler Co-refining System

Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.

Quasi-Solid-State Composite Electrolytes with Multifunctional 2D Molecular Brush Fillers for Long-Cycling Lithium Metal Batteries

The ever-growing demand for next-generation high-energy-density devices drives the development of lithium metal batteries with enough safety and high performance,in which quasi-solid-state composite electrolytes(QSCEs)with high ionic conductivity and lithium ion transference number(urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0001)are highly desirable.Herein,we successfully synthesize a kind of two-dimensional(2D)molecular brush(GO-g-PFIL)via grafting poly(ionic liquid)side-chain(poly(3-(3,3,4,4,4-pentafluorobutyl)-1-vinyl-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide),denoted as PFIL)on the surface of 2D graphene oxide(GO)sheet.GO-g-PFIL is used as multifunctional filler to prepare novel composite membranes and corresponding QSCEs(e.g.,QSCE-PH/GPFIL3/P).The as-obtained QSCE-PH/GPFIL3/P integrates features of PFIL side-chain-enhanced lithium ion conduction,poly(vinylidene fluoride-co-hexafluoropropene)backbone-induced flexibility,and GO-strengthened mechanical property.As a result,our ultrathin(21μm)self-supporting QSCE-PH/GPFIL3/P exhibits high ionic conductivity(3.24×10^(−4)S·cm^(−1))and excellent urn:x-wiley:1001604X:media:cjoc202300232:cjoc202300232-math-0002(0.82)at room temperature,and Li/LFP full cell with QSCE-PH/GPFIL3/P shows superior rate performance(high specific capacities of 79 mAh·g^(−1)at 30°C and 5 C)and excellent cycling performance(high capacity retention of 91%after 500 cycles at 80°C and 1 C).

Wetting behavior of AgCu-4.5Ti filler reinforced by carbon nanotubes on C/C composite

The effect of Carbon Nanotubes(CNTs)content on the wettability of AgCu-4.5Ti+x CNTs(wt%)composite filler alloys on C/C composite was investigated.The results show that the added CNTs reacted with element Ti in the filler and produced the dispersed fine in situ synthesized TiC particles,which increased the consumption of element Ti and provided the nucleus for the growth of Ti-Cu compounds simultaneously.The above effects of introducing CNTs,inhibited the formation of Ti-Cu compounds,also changed the distribution of compounds,which dramatically influenced the interfacial microstructure and characteristics of wetting behavior.The increase of CNTs content refined and dispersed coarse Ti-Cu compounds,decreased the initial spreading temperature,and improved the wettability,but high content of CNTs(more than 0.3 wt%)decreased the wettability of the filler alloy.The wetting interfacial microstructure of corresponding composite filler alloys were analyzed by Scanning Electron Microscope(SEM),Energy Dispersive X-ray Spectrometer(EDS)and Transmission Electron Microscope(TEM),which consisted of TiC,TiCu,TiCu;and TiCu;compound.The typical wetting behavior of AgCu-4.5Ti+0.3wt%CNTs composite filler on C/C composite was divided into four stages.The effect mechanism of CNTs content on the wetting behavior was proposed.

Microstructural evolution and mechanical properties of brazed IN718 ultrathin-walled capillary structure using different particulate reinforced filler alloy

The development of hypersonic precooled combined cycle engine provides a reliable power system for the future intercontinental navigation and reusable space orbital transportation.The compact heat exchanger precooler is the key component of the cooling cycle system,which provides efficient heat management for the hypersonic engine.This investigation mainly focused on the manufacturing process of precooler,and the typical structure of the precooler,ultrathin-walled capillary structure,was facilitated by the vacuum brazing using the particle reinforced composite filler alloy.The effects of different types and contents of the reinforced particle on the spreading behaviour,microstructural evolution,mechanical performance changes were investigated in detail.During the cooling process,the nucleation and growth of the c-Ni solid solution on the surface of the reinforced particles was the main reason for the microstructure homogenization.Compared to the Ni particles,the more obvious mechanical properties improvement could be achieved by using IN718 particles reinforced composite filler alloy.The tensile strength and elongation of the brazed ultrathin-walled structure present 9.36%and 47.27%higher than that using initial filler alloy.Moreover,the micro-hardness distribution result revealed that the reinforced particles reduced the overall micro-hardness of the brazed region,dispersed the eutectic structure and increased the hardness dispersion,which would reduce the stress concentration tendency and improve the structural properties.

Effects of Filler Metal Composition on Inclusions and Inclusion Defects for ER NiCrFe-7 Weldments

The effects of filler metal （FM） composition on inclusions and inclusion defects for ER NiCrFe-7 weldments have been investigated and analyzed. Results show that as Al, Ti content in FM increases from 0.14 wt% Al, 0.30 wt% Ti to 0.42 wt% Al, 0.92 wt% Ti, the Al, Ti reduction will increase during welding. Inclusion defects （point-like defects named by welding workers） are prone to form in the high Al, Ti content weldments. Inclusion defects with Mg, Ca, Al, and Ti as major metallic elements have been found on the surface and interior of the weldments, as Al, Ti content in FM is over 0.29 wt% Al, 0.62 wt% Ti. Less -ri content in FM cannot prevent ductility-dip-cracking （DDC） through producing enough intragranular precipitates and lessening intergranular M23C6 precipitates. Nb can be used to replace Ti to reduce the sensitivity of the DDC in the NiCrFe-7 alloy weldments.

Interfacial characteristics in CNTs-AgCuTi systems

AgCuTi-based composite fillers reinforced with Carbon Nanotubes(CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy(FESEM), XRay Diffraction(XRD) and a Differential Scanning Calorimeter(DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy(TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system.The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure.Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu;with high Ti content and Ti;Cu;phases to TiCu;phase with low Ti content. Additionally,the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs.Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.

Recycling polymeric waste from electronic and automotive sectors into value added products

The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a global waste management issue. The addition of up to 25% polymeric waste PCBs （printed circuit boards） as fillers in polypropylene （PP） composites was partially successful： while the tensile modulus, flexural strength and tlexural modulus of composites were enhanced, the tenstle and impact strengths were found to decrease. As a lowering of impact strength can significantly limit the application of PP based composites, it is necessary to incorporate impact modifying polymers such as rubbery particles in the mix. We report on a novel investigation on the simultaneous utilization of electronic and automotive rubber waste as fillers in PP composites. These composites were prepared by using 25 wt.% polymeric PCB powder, up to 9% of ethylene propylene rubber （EPR）, and PP： balance. The influence of EPR on the structural, thermal, mechanical and rheological properties of PP/PCB/ EPR composites was investigated. While the addition of EPR caused the nucleation of the I~ crystalline phase of PP, the onset temperature for thermal degradation was found to decrease by 8%. The tensile modulus and strength decreased by 1 b% and 19%, respectively; and the elongataon at break increased by -71%. The impact strength showed a maximum increase of-18% at 7 wt.%-9 wt.% EPR content. Various rheological properties were found to be well within the range of processing limits. This novel eco-friendly approach could help utilize significant amounts of polymeric electronic and automotive waste for fabricating valuable polymer composites.