Effect of Cold Plasma Treatment on the Mechanical Properties of RTM Composites

Cold plasma technology was used to treat the surface of carbon fibers braided by PET in this paper and SEM was used to analyze the fracture microstructure of composite interlaminar shear stress (ILSS). The result shows that the surface polarity of carbon fibers was modified by cold plasma treatment, which increases the impregnation of PET braided carbon fibers during the process of resin flowing, improves the interfacial properties of RTM composites, and therefore enhances the mechanical properties of the KTM composites.     

Hot Extrusion Effect on the Microstructure and Mechanical Properties of a Mg–Y–Nd–Zr Alloy

Strength of Materials - Mg–Zn–Y–Nd alloy was prepared by casting and hot extrusion. The microstructure and mechanical properties of OM, SEM, XRD, TEM, and tensile tests were...     

Effect of Different Aging Processes on the Microstructure and Mechanical Properties of a Novel Al–Cu–Li Alloy

The effects of different aging processes on the microstructure and mechanical properties of a novel Al–Cu–Li alloy have been investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It is found that the tensile properties of a novel Al–Cu–Li alloy are sensitive to aging processes, which correspond to different microstructures. σ(Al_5Cu_6Mg_2) and T_1(Al_2CuLi) phases are the major precipitates for the alloy in T6 aging condition(165 ℃/60 h). After duplex aging condition(150 ℃/24 h + 180 ℃/12 h), σ, θ'(Al_2Cu) and T_1 phases are detected. Only the T_1 phases can be found in the T8 state alloy(6% pre-strain+135 ℃/60 h). The failure modes of alloy in T6 and duplex aging conditions are dimple-intergranular fracture, while typical quasi-cleavage fracture in T8 condition.     

Effect of Compaction Pressure on Structural and Superconducting Properties of Bi-2223 Superconductors

In this work, effects of compaction pressure on the structural and superconducting properties of BSCCO ceramic superconductors were investigated. The study was carried out on two systems which were, System I: Bi_1.7Pb_0.3Sr₂Ca₂Cu₃O _y and System II: Bi_1.6Pb_0.3Ag_0.1Sr₂Ca₂Cu₃O _y , respectively. Ceramic powders were prepared by conventional solid-state reaction method and sintered at 850°C after compaction at five different pressures in the 150–750 MPa range. Critical temperatures of samples were determined by resistivity-temperature determinations made by four-point probe method in liquid nitrogen conditions. XRD analysis was conducted by powder X-ray diffraction method. Morphology of the grains present in the samples were determined by using scanning electron microscope (SEM) photographs at 2 K× and 2.5 K× magnifications for System I and System II, respectively. Sintered densities of the superconducting ceramics were measured by Archimedes water displacement method and unit cell parameters were additionally obtained from XRD data. T _c values for System I was determined to be in the 109–115 K with sample D having the highest T _c of 115 K while T _c varied in the 104–109 K range and sample B had the highest T _c value of 109 K for System II. The transition width, which is a sign of the purity of the samples, was determined to be narrow for both systems. The data obtained from X-ray diffraction measurements have shown that 2223 high-T _c phase was dominant in both systems. The determination of the optimum pellet compaction pressure for BSCCO ceramic superconductors was the main purpose of this work. The results of this work indicated that compaction at around 450 MPa improves the superconducting and structural properties of the BSCCO ceramic superconductors.     

The Effect of Mechanical Vibration on Optical Properties of Infrared Fibers of AgCl–AgBr Composition

Technical Physics Letters - The effect of mechanical vibration on the optical transmission of the infrared fibers of the AgCl0.25Br0.75 and AgCl0.5Br0.5 compositions for 30 h has been studied. It...     

Effect of Liquid–Solid Extrusion on the High-Temperature Compressive Properties of Csf/Mg Composites

Short carbon fiber reinforced Mg matrix composites (C_sf/Mg) were prepared by an infiltration–extrusion integrated technique in which pressure infiltration and liquid–solid extrusion are performed continuously. Their compressive properties were evaluated in the temperature range 20–300°C, and compared with C_sf/Mg composites fabricated by only pressure infiltration technique. The results show that after liquid–solid extrusion, the fiber tended to align along the extrusion direction, and a refined-grain microstructure was obtained, thereby contributing to a significant increase in both compressive strength and yield strength up to 200°C, but they are abnormally lower than those of the infiltrated composite at 300°C due to fiber rotation and a different deformation mechanism related to the finer grain structures.     

Effect of Si,Mn and Al on the Microstructure and Mechanical Properties of ADI Weld Metal

The effects of Si,Mn and Al on the microstructure and mechanical properties of ADl weld have been studied.The microstructure of ADl weld metal mainly consists of bainitic ferrite and retained austenite.Mechanical properties of Adl weld increase with increasing Si content,but an excess of Si(3.79%) results in decreasing the austemperability owing to decreasing the carbon content of the matrix austenite.Mn increases the retained austenite volume fractio,but the ductility and impact toughness of weld obviously decrease with increasing Mn content because of increased amount of martenite and twin martenite.In the range of 0.13%-0.64%Al ,increasing Al content favours improving the mechanical properties of ADl weld.Therefore,it is very important to select suitable Si,Mn and Al contents to improve mechanical properties of ADl weld .     

Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

1. IntroductionAluminum alloy for aircraft industry is requiredto maintain microstructure stabilityt strength andtoughness at temperatures ranging from 100 to 200'Cor even higher. Some rapidly solidified powder metallurgy (RS/PM) experimental alloys, such as ALFe-VSi alloyt have good mechanical properties up to 300'C.But the alloys produced by rapid solidiflcation processing tend to be relatively more costly and moredifficult to prepare than wrought materials fabricatedfrom ingots[1]. Acc…     

Effect of Milling Time on the Microstructure and Tensile Properties of Ultrafine Grained Ni–SiC Composites at Room Temperature

Bulk metallic nickel–silicon carbide nano-particle(Ni–Si CNP) composites, with milling time ranged from8 to 48 h, were prepared in a planetary ball mill and sintered using a spark plasma sintering(SPS)furnace. The microstructure of the Ni–Si CNP composites was characterized by transmission electron microscopy(TEM) and their mechanical properties were investigated by tensile measurements. The TEM results showed well-dispersed Si CNP particles, either within the matrix, between twins or along grain boundaries(GB), as well as the presence of stacking faults and twin structures, characteristics of materials with low stacking fault energy. Dislocation lines were also observed to interact with the Si CNP which were plastically nondeformable. A synergistic relationship existed between Hall–Petch strengthening and dispersion strengthening mechanisms, which was shown to greatly influence the mechanical properties of the Ni–Si CNP composites. Both the maximum yield and tensile strengths were found in the Ni–Si CNP composite with a milling time of 48 h, whereas the increased rate of strengths drastically decreased in material milled above 8 h due to the significant Si CNP agglomeration. The ball milling process resulted in the formation of nano-scale, ultra-fine grained(UFG) Ni–Si CNP composites when the milling time was extended for longer periods, greatly strengthening these materials. The sharp decrease in elongation percentages, however, should be comprehensively considered before irreversible inelastic deformation.     

Effect of Holding Time on Microstructure and Mechanical Properties of Dissimilar γ'-Strengthened Superalloys TLP Joint

To achieve efficient connectivity of dissimilar γ'-strengthened superalloy, transient liquid-phase (TLP) diffusion bonding of 718Plus and Ni₃Al-based superalloys is carried out using BNi-2 interlayer at a constant temperature of 1100 °C with holding times of 3, 15, 30, and 60 min. It is shown in the results that when the holding time is insufficient, isothermal solidification transforms into athermal solidification. Due to the enrichment of B and Cr elements in liquid phase, ternary eutectic consisting of γ, Ni₃B, and CrB is formed at the joint center. Ternary eutectic with higher hardness (≈600 Hv) is poorly bonded to the matrix, which can easily become crack initiation location and significantly deteriorated the tensile properties. In addition, microhardness of the joint becomes more uniform and tensile strength gradually increases due to the reduction of eutectic with holding time increasing. Isothermal solidification completes and a joint without eutectic structure is formed at 1100 °C for 60 min. Diffusion of Al atoms leads to the formation of γ' with gradient size and tensile strength is comparable to that of base metal which is about 690.93 MPa.     

Effect of Zn on the Mechanical Properties and Microstructure of as-Cast and Solution-Treated Mg–6Y–2Nd–1Gd–0.5Zr Alloys

Strength of Materials - The effect of varying Zn contents (0, 0.4, and 0.8 wt.%) on the microstructure and mechanical properties of an Mg–6Y–2Nd–1Gd–0.5Zr alloy was...     

Electrical and Mechanical Behavior of Aerosol Jet–Printed Gold on Alumina Substrate for High-Temperature Applications

There is a growing interest in the development of microelectronics that can perform reliably and robustly at temperatures above 300 °C. Such devices require stable thermal properties, low thermal drift, and thermal cycling resistance. Conventional hybrid circuit technology demonstrates high-temperature packages, but the high costs and lead time are significant drawbacks. In contrast, additive manufacturing processes, including aerosol jet printing (AJP), offer cost and time benefits, as well as 3D structures and embedded features. However, the properties and reliability of additive packaging materials at extreme temperatures are not well known. Herein, the reliability at temperatures up to 750 °C in terms of electrical performance and mechanical strength of aerosol jet printed gold thick films onto ceramic substrates are assessed. Thermal coefficient of resistance of printed gold films is measured. The electrical resistance stability and leakage current of printed gold structures are also characterized during over 100 h of aging at temperatures up to 750 °C. Finally, the mechanical adhesion strength of the printed gold films is evaluated after aging for 100 h at temperatures up to 750 °C. The adhesion of the printed gold to the ceramic substrates remains high after aging, very stable resistances and minimal leakage currents have been observed.     

Microstructure and Mechanical Properties of C/(ZrB2–SiC) Composites Produced from Ceramic Ribbons

Inorganic Materials - We have studied the morphology, texture, and bending strength of Cf/(ZrB2–SiC) continuous carbon fiber-reinforced ceramic composite materials prepared by a new method...     

Effect of Nb on the Microstructure and Mechanical Properties of Cast NiAl-Cr（Mo） Eutectic Alloy

The microstructure and mechanical behaviors of NiAl-28Cr-5Mo-1Nb eutectic alloy were investigated by using scanning electron microscopy, X-ray diffraction, transmission electron microscopy and compression tests, respectively. The alloy is mainly composed of three phases, which are the gray lamellar Cr（Mo） plate, black NiAI matrix and semicontinuously distributed Cr2Nb-type Laves phase. Through Nb addition, NiAl-Cr（Mo）/Nb alloy exhibits a reasonable balance of high temperature strength and room temperature compression ductility and its mechanical behaviors are superior to the NiAl-28Cr-6Mo eutectic alloy at all temperature. The elevated temperature compression deformation behavior of NiAl-Cr（Mo）/Nb alloy can be properly described by power-law equation.the National High Technology Committee of China （No. 863-715-005-0030） for financial supports.     

The Role of Rare Earth (Y) Ions on the Structural,Magnetic and Mechanical Properties of Co–Mg Nanoferrites

The current paper is an effort to investigate the impact of rare earth yttrium on magnetic and mechanical properties of novel Co–Mg–Y nanoparticles. A series of ferrite nanoparticles, with a constant amount of cobalt and magnesium, substituted with various amounts of Y³⁺ as Co_0.7Mg_0.3Y_xFe_2-xO₄ (labeled as CMYF nanoferrites) were prepared and studied. The prepared CMYF samples were well investigated for structure and morphology utilizing x-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), and Fourier-transform infrared (FTIR) analysis. The crystallite size of CMYF nanoferrites introduced an abnormal behavior with further Y³⁺ substitution, ranging from 33.33 to 66.89 nm. The nanoferrite Co_0.7Mg_0.3Y_0.08Fe_1.92O₄ (x?=?0.08) has the highest coercivity (1410 G) within all CMYF samples, with increasing ratio 36.10% than the pristine Co–Mg nanoferrite. Also, the nanoferrite Co_0.7Mg_0.3Y_0.1Fe_1.9O₄ (x?=?0.1) has the highest resistance to uniform compression with increasing ratio 8.21% than the pristine nanoferrite. Shear and Young moduli introduced a peculiar trend: decrease regularly for 0.0?≤?x?≤?0.08 and then increase for the nanoferrite with x?=?0.1. Poisson’s ratio values confirmed that all CMYF nanoferrites are stable, isotropic, and linear elastic materials. Hosselman and Fulrath’s model was utilized to correct elastic moduli to zero porosity, which confirmed that porosity is a significant parameter for CMYF nanoferrite elastic moduli determination. Therefore, we conclude that Co_0.7Mg_0.3Y_0.08Fe_1.92O₄ nanoferrite can be utilized in storage media applications and Co_0.7Mg_0.3Y_0.1Fe_1.9O₄ nanoferrite in diverse ferrite standard mechanical applications.