Micro friction stir welding of copper electrical contacts

The paper presents an analysis of micro friction stir welding (μFSW) of electrolytic tough pitch copper (CuETP) in a lap and butt joint. Experimental plan was done in order to investigate the influence of tool design and welding parameters on the formation of defect free joints. The experiments were done using universal milling machine where the tool rotation speed varied between 600 and 1 900 rpm, welding speed between 14 and 93 mm/min and tilt angle between 3° and 5°. From the welds samples for analysis of microstructure and samples for tensile tests were prepared. The grain size in the nugget zone was greatly reduced compared to the base metal and the joint tensile strength exceeded the strength of the base metal

Dependence of mechanical properties on Cu content in AlSi9Cu3(Fe) alloy

Legura aluminija AlSi9Cu3(Fe) je jedna od najčešće korištenih aluminijevih legura jer je njezina primjena temeljena na dobrim mehaničkim svojstvima. U proizvodnji često nastaju odstupanja od maksimalno dopuštenih granica pojedinih legirajućih elemenata, posebice bakra. Budući da mehanička svojstva gotovih proizvoda iz ovih legura ovise o sadržaju bakra, različiti udjeli bakra su dodavani osnovnoj leguri, a sadržaj kemijskih elemenata je praćen pomoću optičkog spektrometra, ispitivanja tvrdoće HB i mjerenja vlačne čvrstoće. Uz ova ispitivanja, analiziran je i utjecaj bakra na oksidacijska svojstva i korozijsku postojanost. Najbolji rezultati dobiveni su za 3 wt. % udjela Cu.AlSi9Cu3(Fe) aluminium alloy is one of the most commonly used casting aluminium alloys because their utility is based on good mechanical properties. Production often leads to deviations of maximum levels for certain alloying elements, particularly copper. Since mechanical properties of the final products of these alloys strongly depend on the concentration of copper in the alloy, various concentrations of copper were added to the basic alloy whereas the chemical composition was monitored using an optical emission spectrometer, measuring Brinell hardness and doing tensile tests. Moreover, the impacts of copper on oxidizing and corrosion resistance of the experimental alloys were analysed. The alloy with 3 wt. % Cu showed the best results

The effect of annealing time on microstructure and impact energy of stainless steel AISI 316L

In this work the results of microstructural analysis and impact energy testing of austenitic stainless steel AISI 316L were carried out. Investigations were performed before and after annealing at 850 °C. Annealing time in this investigation varied from 30 to 90 minutes. After annealing, the samples were cooled in room temperature air. Microstructural analysis of initial rolled and different annealed states was performed by optical microscopy (OM) and scanning electron microscopy (SEM) equipped with device for energy dispersive spectroscopy (EDS). Impact tests were performed on Charpy V-notch specimens at room temperature. Initial rolled state of investigated steel showed the presence of typical elongated polygonal grains austenite and delta ferrite while annealed states showed the presence and evolution of sigma phase in microstructure. Impact energy value of initial rolled state was 260 J and by increasing annealing time it decreases

The effect of annealing time on microstructure and impact energy of stainless steel AISI 316L

In this work the results of microstructural analysis and impact energy testing of austenitic stainless steel AISI 316L were carried out. Investigations were performed before and after annealing at 850 °C. Annealing time in this investigation varied from 30 to 90 minutes. After annealing, the samples were cooled in room temperature air. Microstructural analysis of initial rolled and different annealed states was performed by optical microscopy (OM) and scanning electron microscopy (SEM) equipped with device for energy dispersive spectroscopy (EDS). Impact tests were performed on Charpy V-notch specimens at room temperature. Initial rolled state of investigated steel showed the presence of typical elongated polygonal grains austenite and delta ferrite while annealed states showed the presence and evolution of sigma phase in microstructure. Impact energy value of initial rolled state was 260 J and by increasing annealing time it decreases

Corrosion behavior of CuAlMn and CuAlMnNi alloy in 0.9% NaCl solution

Corrosion behavior of CuAlMn and CuAlMnNi alloy ribbons, produced by melt spinning method, were investigated by electrochemical methods such as open circuit potential measurement, linear and potentiodynamic polarization method. Investigations were performed in deaerated 0.9% NaCl solution (T = 37 °C pH = 7.4). Results of electrochemical investigations have shown that CuAlMnNi alloy have higher values of polarization resistance and smaller values of corrosion current density, but in higher anodic potentials region anodic current density for CuAlMn is lower than for CuAlMnNi alloy which indicates higher dissolution of CuAlMnNi alloy. After polarization measurements CuAlMn and CuAlMnNi ribbon surfaces were investigated with light microscope and with SEM/EDS analysis and results have shown that CuAlMnNi alloy is prone to pitting corrosion, while the surface of CuAlMn alloy is partially covered with corrosion product without existence of pits

Influence of Mn on the corrosion behavior of CuAlMn alloy in NaCl solution

The corrosion behavior of different CuAlMn shape memory alloys (Cu-12%Al-4%Mn, Cu-12.3%Al-5.2%-Mn and Cu-12%Al-6%Mn) in 0.9% NaCl solution at pH = 7.4 and T = 37°C was investigated using open circuit potential measurements, polarization and electrochemical impedance spectroscopy methods. It has been found that the corrosion resistance of the tested samples at open circuit potential increases with increasing Mn content in the alloy, i.e. growing in the order of: Cu-12%Al-4% Mn 0.1 V), the corrosion rate increases with Mn content in the alloy, and light microscopy investigations reveal pits on the surface of Cu-12.3%Al-5.2%-Mn and Cu-12%Al-6%Mn alloys, while Cu-12%Al-4%Mn surface is almost clear of any corrosion damage

Influence of Mn on the corrosion behavior of CuAlMn alloy in NaCl solution

The corrosion behavior of different CuAlMn shape memory alloys (Cu-12%Al-4%Mn, Cu-12.3%Al-5.2%-Mn and Cu-12%Al-6%Mn) in 0.9% NaCl solution at pH = 7.4 and T = 37°C was investigated using open circuit potential measurements, polarization and electrochemical impedance spectroscopy methods. It has been found that the corrosion resistance of the tested samples at open circuit potential increases with increasing Mn content in the alloy, i.e. growing in the order of: Cu-12%Al-4% Mn 0.1 V), the corrosion rate increases with Mn content in the alloy, and light microscopy investigations reveal pits on the surface of Cu-12.3%Al-5.2%-Mn and Cu-12%Al-6%Mn alloys, while Cu-12%Al-4%Mn surface is almost clear of any corrosion damage

Corrosion behavior of CuAlMn and CuAlMnNi alloy in 0.9% NaCl solution

Corrosion behavior of CuAlMn and CuAlMnNi alloy ribbons, produced by melt spinning method, were investigated by electrochemical methods such as open circuit potential measurement, linear and potentiodynamic polarization method. Investigations were performed in deaerated 0.9% NaCl solution (T = 37 °C pH = 7.4). Results of electrochemical investigations have shown that CuAlMnNi alloy have higher values of polarization resistance and smaller values of corrosion current density, but in higher anodic potentials region anodic current density for CuAlMn is lower than for CuAlMnNi alloy which indicates higher dissolution of CuAlMnNi alloy. After polarization measurements CuAlMn and CuAlMnNi ribbon surfaces were investigated with light microscope and with SEM/EDS analysis and results have shown that CuAlMnNi alloy is prone to pitting corrosion, while the surface of CuAlMn alloy is partially covered with corrosion product without existence of pits

Corrosion investigation of rapidly solidified Cu- Al-Ni alloy in NaCl solution

The corrosion behavior of the Cu-Al-Ni alloy ribbons obtained by rapid solidification was investigated in 0.9% NaCl solution (pH 7.4) at temperatures of 24, 37 and 50 ºC. Measurements have been performed by electrochemical methods such as monitoring the open circuit potential, linear and potentiodynamic polarization methods. The influence of chloride ions concentration on corrosion of Cu-Al-Ni ribbons has also been investigated in 0.1% and 1.5% NaCl solution. Results of the investigations have shown that an increase in chloride concentration and electrolyte temperature leads to increase the corrosion current density and decrease the polarization resistance values which mean higher corrosion attack on Cu-Al-Ni alloy. Microscopic images have shown significant pitting corrosion damages on the Cu-Al-Ni alloy surface. Increasing the electrolyte temperature increases the surface damages of the electrode due to more intense corrosion. SEM surface images of Cu-Al- Ni electrodes have confirmed that with the elevation of chloride concentration a more intense corrosion attack occurs. EDS surface analysis indicated dominant percentage of copper, chlorine and oxygen on the surface, indicating the formation of copper oxide and chloride as the major corrosion products on the surface. The presence of a small percentage of aluminum indicates its distribution in the form of aluminum oxide and chloride in the surface layer

The influence of pH and electrolyte temperature on corrosion behaviour of CuAlMnTi alloy ribbons in NaCl solution

The influence of pH and temperature of 0.9% NaCl solution on corrosion behavior of CuAlMnTi alloy ribbons, produced by rapid solidification using melt spinning method, were investigated by electrochemical methods. Open circuit potential measurement, linear and potentiodynamic polarization were employed during the investigation, and the measurements were conducted in the electrolyte temperature of 10, 24, 37 and 50 oC and in solution pH of 7.4, 5.4 and 3.4. In has been found that corrosion rate generally increase with increasing the temperature of the electrolyte while the influence of pH change on CuAlNiTi ribbon corrosion is little less pronounced. After polarization measurements CuAlNiTi ribbon surfaces were investigated with light microscope and with SEM/EDS analysis