Sharif Digital Repository

In this study, SiC/Ti–Cu nanocomposite was fabricated by mechanical alloying and sintering process. Effects of SiC nano-reinforcement on phase transformation, microstructure and tribological and antibacterial properties Ti–Cu intermetallic alloy were studied. The microstructure of the powders and sintered materials was investigated using X-ray diffraction, and scanning/transmission electron microscopy. The results exhibited the formation of major TiCu and TiCu 4 , and minor Ti 2 Cu and Ti 2 Cu 3 nanocrystalline phases in the sintered Ti–Cu and SiC/Ti–Cu samples. With the addition of the nanoparticles, the amount of TiCu 4 phase increased. Reinforcing Ti–Cu intermetallic alloy by SiC... 

The demands for high-performance biomaterials are driving the development of new metallic alloys with improved mechanical and biological responses. In this study, a nanocrystalline Ti-Cu intermetallic alloy was prepared by a powder metallurgy route, and its application as an orthopedic material was evaluated by the microstructural, mechanical, corrosion, antibacterial, cytotoxicity and osseointegration examinations. Microstructural characterization revealed the formation of TiCu and Ti2Cu3 as major phases with 23 nm grain size in the structure of the alloy. The synthesized alloy exhibited ultra-high hardness of 10 GPa, acceptable toughness of 8.14 MPam1/2, a ∼98 % anti-bacterial rate against... 

Effects of SiC nanoparticles addition on synthesis and antibacterial properties of TiCu nanocrystalline powder prepared through high energy mechanical milling were studied. The results showed that the synthesis of TiCu powder in the presence of the nanoparticles was accelerated and after mechanical alloying for 20 h, a TiCu/SiC nanocrystalline powder with the crystallite size <5 nm, and 3.3% lattice micro-strain obtained. Further milling resulted in fully amorphous TiCu intermetallic alloy with more uniform distribution of SiC nanoparticles. The antibacterial activity of the synthesized powders was investigated by disk diffusion test. The TiCu/SiC nanocomposites showed enhanced antibacterial... 

Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding... 

In this paper, ultra-small CuO nanoparticles (NPs) were synthesized through a mechanochemical method using two different Cu-containing precursors (i.e. CuSO4·5H2O and CuCl2·2H2O), and their structure and antibacterial activity were studied. From the microstructural studies, it was observed that CuO NPs have a spherical morphology and a narrow size distribution with 7 and 14 nm median particle sizes for CuCl2·2H2O and CuSO4.5H2O precursors, respectively. The CuCl2·2H2O derived nanoparticles showed more antibacterial activity than CuSO4.5H2O derived nanoparticles. The minimum inhibitory concentration (MIC) of the synthesized nanoparticles (derived from both precursors) against E. coli and... 

In the present research, different weld layers were deposited on a 1.2714 steel die by gas tungsten arc (GTA) welding with the weld wire of Udimet 520, and effects of welding parameters on microstructure and mechanical properties of Udimet 520 superalloy were investigated. The results showed Udimet 520 weld with cellular-dendritic and rarely dendritic structure including γ matrix rich of Cr, Mo and W, low percentage associated with order morphology and relative uniform distribution of MC type carbides. Udimet 520 alloy showed high resistance against hot cracking during welding and hot cracking occurred only at high input heat values. Also, cracking during welding occurred at the places that... 

In this research, carbon nanotube decorated with Cu nanoparticles (CNT/Cu) was synthesized by a new solvothermal process. Solvothermal treatment of CuSO4 and NaOH was completed in ethanol containing ultrasonically dispersed CNTs at 160 °C for 3 h. In the solvothermal process, Cu nanoparticles were heterogeneously deposited on the surface of COOH-functionalized CNTs through the reduction of the Cu+2 ions. Cu nanoparticles with the size of ≈8 nm on CNTs (and some in the solution) and strong bonding between Cu and CNT were obtained by the used process. Microstructural characterization revealed that the solvothermal method is an appropriate method for producing homogenous CNT/Cu nanostructure.... 

Titanium (Ti) has been widely used for manufacturing of bone implants because of its mechanical properties, biological compatibility, and favorable corrosion resistance in biological environments. However, Ti implants are prone to infection (peri-implantitis) by bacteria which in extreme cases necessitate painful and costly revision surgeries. An emerging, viable solution for this problem is to use copper (Cu) as an antibacterial agent in the alloying system of Ti. The addition of copper provides excellent antibacterial activities, but the underpinning mechanisms are still obscure. This review sheds light on such mechanisms and reviews how incorporation of Cu can render Ti–Cu implants with...