Microstructure and Mechanical Properties of Commercially Pure Ti/Steel Joint Brazed by Zr-Ti-Ni Amorphous Filler Metal.

In this study, the characteristics of commercially pure titanium (hereinafter referred as CP-Ti)/Steel joints, brazed with Zr-Ti-Ni amorphous filler metal were analyzed. The effects of brazing temperature and time on the microstructure and joining strength of the CP-Ti/Steel joints were investigated. It was observed that Ti diffused into stainless steel substrate formed a brittle reaction zone, which contained intermetallic compounds, such as τ (TiCrFe), (Fe, -Ni)Ti, and FeTi, observed at the joint interface.

Dislocation Structure in Hot Deformed Al-Zn-Mg Alloy by X-ray Line Profile Analysis.

The microstructure of extruded Cu-free Al-Zn-Mg alloy is studied. Hot torsion tests are performed on a Cu-free Al-Zn-Mg alloy to investigate the effect of large strain deformation on the dislocation behavior. The dislocation structure is characterized by X-ray diffraction profile analysis, and the effective stress-strain curves are obtained by hot torsion tests.

High Temperature Deformation Characteristics of Al-Zn-Mg Alloy Modified with CaO-Added Mg.

Hot torsion tests were performed on an Al-Zn-Mg alloy modified with CaO-added Mg to investigate the effects of the Mg additive on the high temperature deformation characteristics. Effective stress- strain curves and processing maps were established from the experimental results under a range of deformation conditions. The fracture strain of the CaO-added Al-Zn-Mg alloy was higher than that of the Al-Zn-Mg alloy.

Microstructural and Mechanical Characteristics of A356 Alloys as a Function of Mn Content and Cast Thickness.

In this study, the changes in the microstructural characteristics and mechanical properties of A356 alloys as a function of Mn content and cast thickness were evaluated using structural analysis and tensile tests. Five different A356+%Mn alloys were prepared by casting in molds of different thicknesses followed by solid solution treatment at 813 K for 195 min and aging treatment at 423 K for 120 min. It was confirmed that the secondary dendrite arm spacing (SDAS) increased with increasing thickness of the cast sample, whilst, for a given thickness, the addition of small amounts of Mn resulted in a decrease of the SDAS.

Brazing Characteristics and Bonding Strength of Pure Titanium Joints Brazed with Low-Melting Temperature Zi-17Ti-22Ni Filler Metal.

The brazing characteristics and bonding strengths of pure titanium joints are evaluated for joints brazed with Zr-17Ti-22Ni filler. Vacuum brazing was conducted at temperatures between the melting temperatures of the filler metals and the beta-transition temperature of pure titanium at 3 MPa of pressure for 5 min. Fracturing of the pure titanium joint brazed at 1,093 K occurred before yielding during the tensile tests owing to the presence of a serious segregation region containing harder and more brittle [Ti, Zr]2Ni intermetallic compounds.

Pore Characteristics of Lotus-Type Porous Cu-Fe and Cu-Cr Alloys Fabricated by Unidirectional Solidification.

Lotus-type porous Cu-Fe and Cu-Cr with long cylindrical pores was fabricated by centrifugal casting under hydrogen atmosphere and the effect of alloying elements on pore characteristics of lotus-type porous Cu was investigated. For the lotus type porous Cu-Fe alloy, the porosity slightly decreased and the average pore diameter slightly increased with increasing Fe content. For the lotus-type porous Cu-Cr alloy, the porosity sharply decreased and the average pore diameter drastically increased with an increase in the Cr content.

Effect of Zn on Pore Characteristics in Lotus-Type Porous Cu.

The effect of Zn on pore characteristics in lotus-type porous Cu alloy was investigated. The lotustype porous Cu-Zn alloys were fabricated with Zn content from 0.01 to 0.

Hot Deformation Behavior of Hot-Extruded AA7175 Through Hot Torsion Tests.

The hot deformation behavior of hot-extruded AA7175 was investigated with flow curves and processing maps through hot torsion tests. The flow curves and the deformed microstructures revealed that dynamic recrystallization (DRX) occurred in the hot-extruded AA7175 during hot working. The failure strain was highest at medium temperature.

Preparation and Properties of WC-Based Alloy Coatings with Controlled Co and Cr via High Velocity Oxy-Fuel Spray Technique.

WC based alloy coatings included different mass percent of Co and Cr have been synthesized on high carbon steel by using a facile high velocity oxy-fuel spray method. The mechanical nature of the coating films has been investigated by micro vickers hardness and fracture toughness. X-ray diffraction (XRD) and EDX analyses indicate that the three different samples (WC-10Co-4Cr, WC-17Co, and WC-12Co) consist of pure WC, W, Cr, and Co constituents as well as W2C and Co6W6C phases.

Effect of the Spray Distance on the Properties of High Velocity Oxygen-Fuel (HVOF) Sprayed WC-12Co Coatings.

In this study influence of spray distance on the properties of WC-12Co coatings deposited by HVOF was investigated. WC-12Co coating was sprayed at spray distance of 300, 385 and 450 mm. From microstructure observation, it is confirmed that the porosity of coatings increases with increasing the spray distance.

Effects of Heat Treatment on Interfacial Behavior and Bonding Strength of Surface Activated Bonding Ti-Al Laminate.

The surface activated bonding (SAB) method generally has the advantage of high bonding strength, low contact resistance, and high microstructural stability at room temperature. In this study, Ti-Al laminates were produced by surface activated bonding with aluminum and titanium foils. Heat treatment was conducted at the temperature range from 200 to 550 °C in vacuum.

Improved Sensing Behaviors in Reduced Graphene Oxide Functionalized with Ni(OH)2 Nanoparticles.

In this paper, we detail improvements in the sensing properties of reduced graphene oxide (RGO), which were achieved through functionalization. The functionalization process utilizes graphene oxide suspensions, generating nanoparticles on the RGO surface mainly comprised of Ni(OH)2 phase. Raman spectra indicate that functionalization increases the degree of disorder in RGOs.

Effect of Radio Frequency Plasma Treatment on Evaporation Behavior and Characteristics of RuCr Alloy Powder.

The evaporation behavior and characteristics of jet milled RuCr alloy powders processed by radio-frequency (RF) plasma treatment were evaluated during this study. RF plasma treatment was found to be effective in eliminating internal pores and in manufacturing spherical powder. However, the RF plasma treatment resulted in the evaporation of Cr.

Microstructure and properties of cross-roll rolled and heat treated metastable TiNbSn alloy.

A (Ti-35mass%Nb)-4mass%Sn alloy was cross-roll rolled with a reduction ratio of 70% in which the roll axes are tilted by ± 5 degrees away from the transverse direction of the rolled sample and then aged at 250 degrees C for 2 h. Cross-roll rolling was found to increase yield strength and Young's modulus, simultaneously. Yield strength was higher in cross-roll rolled than in conventionally rolled at same reduction ratio.

Effect of swaging on Young׳s modulus of β Ti-33.6Nb-4Sn alloy.

The effect of swaging on the Young's modulus of β Ti-33.6Nb-4Sn rods was investigated by X-ray diffraction, thermography, microstructural observations, deformation simulator analysis and cyclic tensile deformation. Stress-induced α″ martensite was stabilized by swaging, dependent on the diameter reduction rate during swaging.

Fabrication of a high-performance hip prosthetic stem using β Ti-33.6Nb-4Sn.

This study used severe cold rolling followed by cold swaging of β Ti-33.6% Nb-4% Sn rods to form a characteristic fiber structure composed of stress-induced α″ martensite with <010> texture and a β phase with <101> texture, resulting in a material with a low Young's modulus of 40GPa. The material's tensile strength of 1270MPa and fatigue strength of 850MPa were attained by heat treatment at 673K for 5h through fine α precipitation in the fiber structure.

Synthesis of nanoparticles using electrical explosion of Ni wire in Pt solution.

The structure, size and morphology of nanoparticles produced by electrical explosion of Ni wire in Pt(NH3)2(NO2)2 solution were investigated. TEM results showed the formation of Ni and Pt nanoparticles as a result of the procedure. Ni nanoparticles were formed by the explosion of the Ni wire due to the passage of high current, evaporation, ionization, and cooling in the liquid medium.

Mechanical properties and microstructures of β Ti-25Nb-11Sn ternary alloy for biomedical applications.

The mechanical properties and microstructures of β Ti-25%Nb-11%Sn ternary alloy rods were investigated for biomedical applications as a function of heat treatment temperature after swaging by an 86% reduction in cross-section area. An as-swaged rod consisting of a β (bcc) single phase shows a low Young's modulus of 53 GPa, which is interpreted in terms of both the metastable composition of the β alloy undergoing neither an athermal ω transformation nor a deformation-induced ω transformation and <110>texture development during swaging. Heat treatment at 673 K (400 °C) for 2h leads to a high strength of approximately 1330 MPa and a high spring-back ratio of yield stress to Young's modulus over 15×10(-3), with acceptable elongation.

The bone tissue compatibility of a new Ti-Nb-Sn alloy with a low Young's modulus.

A Ti-Nb-Sn alloy was developed as a new β-type titanium alloy which had a low Young's modulus and high strength. The Young's modulus of the Ti-Nb-Sn alloy was reduced to about 45 GPa by cold rolling, much closer to human cortical bone (10-30 GPa) than that of Ti-6Al-4V alloy (110 GPa) and other β-type titanium alloys developed for biomedical applications. The tensile strength of the Ti-Nb-Sn alloy was increased to a level greater than that of Ti-6Al-4V alloy by heat treatment after severe cold rolling.