This preliminary study characterizes the bronze metalworking on a defensive settlement of the Lusatian culture in former Kamieniec (Chełmno land, Poland) as it is reflected through casting workshop recovered during recent excavations. Among ready products, the ones giving evidence of local metallurgy (e.g. casting moulds and main runners) were also identified. With the shrinkage cavities and dendritic microstructures revealed, the artifacts prove the implementing a casting method by the Lusatian culture metalworkers. The elemental composition indicates application of two main types of bronzes: Cu-Sn and Cu-Pb. Aside these main alloying additions, some natural impurities such as silver, arsenic, antimony and nickel were found which may be attributed to the origin of the ore and casting technology. The collection from Kamieniec was described in terms of its structure and composition. The investigations were made by means of the energy dispersive X-ray fluorescence spectroscopy (ED-XRF), scanning electron microscopy (SEM) coupled with an energy dispersive Xray analysis system (EDS) and optical microscopy (OM). In order to fingerprint either local or non-local profile of the alloys, the ED-XRF data-set was statistically evaluated using a factor analysis (FA).
The microstructure, phase consistence and microhardness of thermal sprayed coatings were investigated. The tungsten and chromium carbide coatings and also composite NiCrSiB coating were analyzed. The microstructure of coatings were observed by using optical microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Almost equiaxial carbide particles settled inside the surrounded material of coating were found. The cracks propagating thorough the particles and along boundaries between the particles and surrounded material were observed. This phenomenon was connected with the porosity of coatings. The decarburization process was detected in coatings by phase composition investigation using X-ray method. The decarburization process was the reason due to which beside initial Cr3C2 the Cr7C3 and Cr23C6 particles were found. In the tungsten coatings beside the initial WC carbides the W2Cones were found.
In this study, four composites with different ZrB2 content were made by the Spark Plasma Sintering (SPS/FAST) technique. The sintering process was carried out at 1373 K for 5 min under an argon atmosphere. The effect of ZrB2 reinforcing phase content on the density, microstructure, and mechanical and tribological properties of composites was investigated. The results were compared with experimental data obtained for 316L austenitic stainless steel without the reinforcing phase. The results showed that the ZrB2 content significantly affected the tested properties. With the increasing content of the ZrB2 reinforcing phase, there was an increase in the Young’s modulus and hardness and an improvement in the abrasive wear resistance of sintered composites. In all composites, new fine precipitates were formed and distributed in the steel matrix and along the grain boundaries. Microstructural analysis (Scanning Electron Microscopy (SEM), Wavelength Dispersive Spectroscopy (WDS)) has revealed that the fine precipitates chromium contained chromium as well as boron.
The studies regard analysis of variable Al and Fe additions on the chosen group of CuSn alloys. The group of tin bronzes known and applied for thousands of years has still found its application in many branches of industry, however it was observed that small amounts of aluminum and iron may affect the original properties strongly. The changes of mechanical properties and microstructure is discussed in detail. Aside of many advantageous properties of these bronzes, it is noted that the mentioned alloying additions have beneficial effect on the gas-induced shrinkage porosity. Simultaneously, the effect of the aluminum addition on the characteristic phase transformation points was determined basing on the analysis of calorimetric curves. The results are correlated with microstructure observations.
Currently there is a constant development in the field of aluminium alloys engineering. This results from, i.a., better understanding of the mechanisms that direct strengthening of these alloys and the role of microalloying. Now it is microalloying in aluminum alloys that is receiving a lot of attention. It affects substantially the macro-and microstructure and kinetics of phase transformation influencing the properties during production and its exploitation. 7xxx series aluminum alloys, based on the Al-Zn-Mg-Cu system, are high-strength alloys, moreover, the presence of Zr and Sr further increases their strength and improves resistance to cracking. This study aims to present the changes of the properties, depending on the alloy chemical composition and the macro-and microstructure. Therefore, the characteristics in the field of hardness, tensile strength, yield strength and elongation are shown on selected examples. Observations were made on ingot samples obtained by semi-continuous casting, in the homogenized state. Samples were prepared from aluminum alloys in accordance with PN-EN 573-3: 2013. The advantage of Al-Zn-Mg-Cu alloys are undoubtedly good strength, Light-weight and resistance to corrosion. As widening of the already published studies it is sought to demonstrate the repeatability of the physical parameters in the whole volume of the sample.
CEC has unique characteristic. These are applicability of very large strain and deformation under high hydrostatic pressure. Due to these abilities of CEC, several unique phenomena have been observed. One of them is the possibility of consolidation of metallic powders in room temperature to the form of bulk material. In the present paper the consolidation of AgSnBi and AgNi to bulk composites was presented. Applying the deformation of = 0.42 in the single cycle of CEC, under high hydrostatic pressure, the samples without pores and discontinuities were fabricated. The microstructure observations were performed by optical microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). They show refinement of microstructure at all levels of observation. The nanometric-size subgrains/grains were found inside consolidated granules. The microhardness level of AgSnBi in average achieved level 110 μHV100, and AgNi of about 90 μHV100. The AgSnBi samples consolidated by CEC and additional hydrostatically extruded to wires with 3 mm in diameter average showed 500 MPa yield point.
In the paper the electrical properties of the Cu/Sn96Ag4 solders were studied. The studied solders were produced at 200, 220 and 250• C and within time range 3 to 90 s. Soldering temperatures were chosen to assure the best soldering conditions for the Cu/Sn96Ag4 alloy. The most appropriate temperature of 200• C is the one just above the melting point. The temperature of 250• C is the maximal one recommended by producers, which can be applied for the electronic elements during soldering. The studies have shown that the best electrical properties and tensile strength R m have samples soldered at times 3 and 30 s, while the highest specific resistance together with the lowest R m value are observed for samples soldered at the time of 10 s. The soldering temperature have small influence on the strength of the connection/bond however it shows significant affect on the electrical properties.Keywords: lead-free solders, electrical properties, intermetallic phases W pracy badano własności elektryczne i mechaniczne połączeń lutowanych Cu/Sn96Ag4. Badane połączenia wykonywano przy temperaturach 200, 220 i 250• C oraz przy czasach lutowania z zakresu od 3 do 90 s. Temperatury lutowania zostały dobrane pod kątem warunków w jakich może być prowadzony proces lutowania przy użyciu stopu Cu/Sn96Ag4. Odpowiednia temperatura 200• C jest tuż powyżej punktu topnienia, a więc najniższa możliwa do zastosowania. Temperatura 250• C jest maksymalną zalecaną przez producentów temperaturą, którą mogą wytrzymać elementy elektroniczne podczas lutowania. Badania wykazały, że najlepsze własności elektryczne oraz wytrzymałość na rozciąganie R m wykazują próbki lutowane przy czasach 3 i 30 s, natomiast najwyższy opór właściwy połączony z najniższą wartością R m zaobserwowano dla próbek lutowanych w czasie 10s. Temperatura lutowania ma niewielki wpływ na wytrzymałość połączenia natomiast w istotny sposób wpływa na własności elektryczne.
In this paper, the results from studies regarding near-eutectic Al-Si alloys with Sn as an alloying addition are presented. In most Al-Si alloys, tin is regarded as a contaminant; thus, its amount is limited to up to 0.3 wt.%. The few studies that can be found in the literature regarding the behaviour of tin in aluminium alloys suggest the beneficial effect of this element on selected properties. However, these results were obtained for hypereutectic Al-Si alloys or wrought aluminium alloys. In our studies, the influence of tin contents of up to 1.7 wt.% was determined on the AlSi10 alloy. Thermal analysis, measurements of the mechanical properties of the cast and heat-treated alloy, metallographic observations (light microscopy, scanning electron microscopy), and EDS (X-ray energy dispersive spectrometry) measurement allowed us to fully describe the effect of tin on the aluminium alloy. The results of the thermal analysis showed changes in the range of the α-Al solution crystallisation and the α+β eutectic through a decrease in the alloy’s solidification start point and eutectic solidification point. As a result, the elongation of the alloy was more than double in the AlSi10Sn1.7 alloy, with an A5 value of 8.1% and a tensile strength that was above 200 MPa.
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