Microstructure and mechanical properties of Cu-Ti alloy by mechanical alloying

Microstructures and formation mechanism of W–Cu composite coatings on copper substrate prepared by mechanical alloying method

Separation of metallic Ti from Cu-Ti alloys through a simple and efficient electrochemical approach

In this study, changes in microstructure, hardness and wear performance of titanium–zirconium–molybdenum (TZM) alloys produced by mechanical alloying method with the addition of different amounts of titanium (Ti) were investigated. Mechanically alloyed powders were sintered at 1300 °C for 4 h under 10–6 mbar vacuum environment. The produced alloys were characterized by scanning electron microscope (SEM + EDS), X-ray diffraction, grain size distribution, hardness and density measurements. In the wear tests, three different loads and five different sliding distances were used. Results showed that the produced TZM alloys were porous, and the pores in the alloys containing 0.40% and 0.45% Ti were generally located on the grain boundaries. In alloys containing 0.50% Ti, inside the grain the pore sizes increase, while in the alloy containing 0.55% Ti, the pore sizes in grain boundary decrease. Grain size distribution results show that as the Ti content increased, the amount of grain size over 6 µm decreased and smaller than 6 µm increased. Hardness and density results show that while the hardness of TZM alloys produced increases depending on Ti content, their density decreases. The highest hardness was obtained in the TZM alloy containing 0.55% Ti, while the lowest density was obtained in the same alloy. Wear test results show that the lowest weight loss was obtained in TZM alloy containing the highest amount of Ti (0.55%) under all loads.

Microstructure and magnetic properties of mechanically alloyed FeSiBAlNi (Nb) high entropy alloys

This study examined the effects of addition of alumina nanoparticles on the microstructure, tribological and corrosion properties of CuTi alloy. Mechanical alloying was performed employing satellite ball milling. X-ray diffraction revealed that CuTi solid solution was formed after 40 h of mechanical alloying. Mechanically alloyed powder was cold-pressed and sintered at 850 °C. Alumina nanoparticles were uniformly dispersed in the CuTi alloy matrix. Tribological properties of the samples were evaluated by pin-on-disk wear testing. The results showed a decrease in wear rate by 30 % owing to the presence of nanoparticles in the nanocomposite. The corrosion properties of samples were assessed employing potentiodynamic polarization and immersion methods in a 3.5 wt.% NaCl solution. The corrosion current density of CuTi alloy decreased from 125.9 to 6.3 μA · cm−2 following the addition of alumina nanoparticles.

Effect of the existing form of Cu element on the mechanical properties, bio-corrosion and antibacterial properties of Ti-Cu alloys for biomedical application

Mechanical alloying (MA) method was applied to nitride Fe–18Cr–11Mn stainless steel powders through aerating nitrogen circularly. Both the MA process and increasing nitrogen pressure circularly caused the expansion of nitrogen solubility in Fe. The microstructure of powders was affected by the milling time. The phase transformation of α-Fe to γ-Fe occurred during the MA process. The grain size of powder decreased, while the internal lattice strain increased by increasing the milling time and cycles of aerating nitrogen. The as-milled powder could obtain a fully austenitic structure after sintering and subsequent water quenching. The sintered samples had better density and higher microhardness when the powders milled for more time. The formation mechanism of nitriding of stainless steel powders using MA method in nitrogen was presented.

The service life as hard tissue implantation for clinical application needs compatible mechanical properties, e.g. strength, modulus, etc, and certain self-healing in case of internal infection. Therefore, for sake of improving the properties of Ti-Cu alloy, the microstructure, mechanical properties, corrosion resistance and antibacterial properties of Ti-xCu alloy (x = 2, 5, 7 and 10 wt.%) prepared by Ar-arc melting followed by heat treatment were studied. The results show that the Ti-Cu alloy was mainly composed of α-Ti matrix and precipitated Ti2Cu phase. The Cu element mainly accumulates in the lamellar structure and forms the precipitated Ti2Cu phase. As the increase of Cu content, the lamellar Ti2Cu phase increases, the compressive strength and elastic modulus also were altered. The Ti-7Cu alloy exhibited the higher compressive strength (2169 MPa) and the lower elastic modulus (108 GPa) compared with other Ti-Cu alloys. The corrosion resistance of Ti-xCu alloys increases with the increase of Cu content. When the Cu content was greater than 5 wt.%, the value of corrosion current density for Ti-Cu alloy was less than 1 μA·cm−2, which is also significantly lower than that of CP-Ti. The antibacterial test revealed that only the Ti-Cu alloy with 5 wt.% or greater Cu content could display a strong antibacterial rate against E. coli and S. aureus. Therefore, the prepared Ti-7Cu alloy via heat treatment showed excellent mechanical properties, corrosion resistance, and antibacterial properties, which would meet the replacement of human hard tissue and clinical applications.

In order to reduce the brazing temperature of Ag-based filler and simultaneously avoid the problem of difficult processing, AgCuSn15 brazing fillers prepared by mechanical alloying method (named MA-1) and layer composite method (named LC-2) were employed to vacuum braze Ni substrate. The microstructure and mechanical properties of Ni/Ni joints brazed using MA-1 and LC-2 were compared. The effects of brazing temperature and brazing time on the mechanical properties of joints brazed using MA-1 were studied. The results suggest that the microstructure of the joint brazed using MA-1 is Ni/(Ni, Cu)3Sn + (Cu, Ni)6Sn5/Ag(s, s)+Cu(s, s)/(Cu, Ni)6Sn5+(Ni, Cu)3Sn/Ni, and there are small cracks caused by Cu6Sn5 phase in the joint. Due to the incomplete alloying of AgCu and Sn, the microstructure of joint brazed using LC-2 is Ni/(Cu, Ni)6Sn5+(Ni, Cu)3Sn/Ag(s, s)+Cu(s, s)+Ag-Cu eutectic/(Ni, Cu)3Sn +(Cu, Ni)6Sn5/Ni. The strength of the Ni/Ni joint brazed using MA-1 is highest (42.74 Mpa) at 680°C for 30 min. The strength of the Ni/Ni joint brazed using LC-2 under the same conditions is 24.86 Mpa.

Influence of Ti and Zr in Cu matrix on the shear strength between Cu-Ti and Cu-Zr alloys and carbon rod was studied. Cu based specimens containing 0.7 and 3.6 wt.% Ti as well as 0.15; 1.3 and 5.1 wt.% Zr were prepared by hot pressing (HP) and hot isostatic pressing (HIP). In all cases, titanium diffuses to the boundary between carbon rod and Cu-Ti alloys and reacts with oxygen forming titanium oxides. Shear strength is higher for HIP specimens and increases with Ti content. The layer adjacent to carbon rod, in the case of Cu-Zr alloys, is pure copper (except for Cu-5.1 wt.% Zr alloy). The shear strength in this case is close to that of pure copper. For Cu-5.1 wt.% Zr the adjacent copper layer to C rod contains Cu-Zr particles. The shear strength is higher compared to Cu-0.15 and 1.3 wt.% Zr alloys, which can be due to the presence of this complex layer.

Investigation of the wear behavior in simulated body fluid of 316L stainless steels produced by mechanical alloying method

Development of tungsten heavy alloy reinforced by cubic zirconia through liquid-liquid doping and mechanical alloying methods

The microstructure and corrosion properties of Fe-Cr-Si alloys prepared by mechanical alloying method were studied using the 57Fe transmission Mössbauer spectroscopy (TMS), x-ray diffraction (XRD), and scanning electron microscope (SEM). The initial ternary mixture in Fe:Cr:Si atomic ratio of 85:10:5 was prepared on the basis of high-purity Fe, Cr, and Si powders. The studied samples were obtained after 10 h (MA-10h), 20 h (MA-20h), and 50 h (MA-50h) of alloying process in planetary ball mill. The SEM results indicate that the mean particle size of prepared material is strongly dependent on milling time and the estimated mean particle sizes were 15.4 (±3.0) μm, 9.0 (±1.5) μm, and 1.73 (±23) μm for MA-10h, MA-20h, and MA-50h, respectively. The XRD and TMS measurements reveal that all the prepared powders are alloys with body-centered cubic (bcc) structure. Moreover, TMS was used to investigate corrosion of Fe-Cr-Si powders during exposure to air at high temperature. The obtained results suggest that reduction of mean particle size of mechanically synthesized alloy drastically decreases its corrosion resistance properties. Finally, the hyperfine field distributions p(B) obtained for MA-10h, MA-20h, and MA-50h samples before and after annealing were compared with the simulated p(B) for a random bcc Fe0.85Cr0.10Si0.05 alloy. This comparison shows that the amount of Cr and Si atoms dissolved in Fe-Cr-Si bcc alloy changes significantly with time of mechanical alloying as well as with annealing.

Binary Ti100-x-Cux (x = 1.6 and 3.0 wt.%) alloys were produced by the application of mechanical alloying and powder metallurgy processes. The influence of the copper concentration in titanium on the microstructure and properties of bulk alloys was investigated. The synthesized materials were characterized by an X-ray diffraction technique, scanning electron microscopy, and chemical composition determination. The electrochemical and corrosion properties were also investigated. Cold compaction and sintering reduced the content of α-Ti content in Ti98.4-Cu1.6 and Ti97-Cu3 alloys to 92.4% and 83.7%, respectively. Open Circuit Potential measurements showed a positive shift after the addition of copper, suggesting a potential deterioration in the corrosion resistance of the Ti-Cu alloys compared to pure Ti. Electrochemical Impedance Spectroscopy analysis revealed significant improvement in electrical conductivity after the addition of copper. Corrosion testing results demonstrated compromised corrosion resistance of Ti-Cu alloys compared to pure Ti. In summary, the comprehensive investigation of Ti100-x-Cux alloys provides valuable insights for potential applications in biosensing.

Recently, [Formula: see text]-based compounds have aroused intensive research interest due to their metal-like ductility, high shape-conformability, and decent thermoelectric (TE) performance at room temperature. The melting–annealing method is commonly adopted to prepare [Formula: see text]-based compounds. Compared with the melting–annealing method, the mechanical alloying (MA) method has the advantages of short period and low cost, but it has not been adopted to prepare ductile [Formula: see text]-based compounds. Herein, we successfully prepare the ductile [Formula: see text] compound by using the MA method. The as-prepared [Formula: see text] products are small spheres with a diameter of several millimeters rather than the powders. These spheres are phase pure with homogeneous element distribution and good deformability. After the consolidation process at 773 K, the [Formula: see text] prepared by using the MA method shows good ductility like that prepared by the melting-annealing method. Finally, a maximum bending strain of above 15%, a maximum compressive strain of above 40%, and a maximum figure-of-merit (zT) of 0.5 are obtained, indicating the feasibility of MA in the preparation of ductile TE compounds.