The anneal hardening behavior of Cu-7at.%Pd alloy after deformation by cold rolling was investigated by means of hardness, microhardness, electrical conductivity, light optical microscopy (LOM), ...scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). In this regard, the cast Cu-7at.%Pd alloy after quenching was deformed with 20% and 40% reductions and isochronally annealed between 100 °C and 700 °C. After annealing up to 400 °C, the deformed samples exhibited atypical anneal hardening behavior in combination with an increase in electrical conductivity. In addition, the recrystallization was substantially retarded by the applied thermo-mechanical treatment which included solution annealing, quenching, cold rolling, and annealing. The microstructural evolution during a low-temperature annealing proved a strong pinning of grain boundaries by solute palladium atoms, indicating that grain boundaries have an important role during the anneal hardening.
•Atypical hardening was appeared in cold deformed Cu-7at.%Pd alloy after low-temperature annealing.•Significant microstructural changes occurred during the thermo-mechanical treatment.•Strong segregation of palladium atoms along the grain boundaries during the annealing has been confirmed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
In the frame of the Romania-Republic of Serbia IPA Cross-border Cooperation Programme, in the Project Ecosolder, the National Research & Development Institute for Welding and Material Testing - ISIM ...Timisoara, Romania, has elaborated a brazing procedure with a new ecological brass of the type B-Cu60ZnSnSiMn, elaborated by the Mining and Metallurgy Institute - MMI Bor, Serbia. The brazing test was carried out according to the standard EN 13134:2000 related to the brazing procedure approval. The applied process is oxygen-acetylene flame brazing of steel sheets, with the sizes of 87 mm x 80 mm, thickness of 1.0 mm and overlap 7 mm. Images of the execution of the brazing procedure are presented, with comments on every phase. The appearance of the joint is adequate, by the visual examination. By the metallographic analysis, the constituents of the deposited filler metal are dendritic solid solution, with fine particles of Sn, Si and Mn. No defects have been revealed. The values of the hardness are 91-133 HV1. The results of the specific shear test comply with the requirements. The technological, ecological, structural and mechanical characteristics of this filler alloy are adequate. Some applications of brazing with the new ecological brass are recommended.
Among ecological solders the SIAC (silver-indium-tin-copper) alloys seemed to be the promising because of their properties. In this paper the results of Ag-In-Sn-Cu electrical conductivity ...measurements are performed as well as polynomial regression of the same. These results are obtained for different temperature regimes and conditions.
Two Cu-Zn-Al alloys with variable content of Zn (25 and 30 wt%) and constant Al content (4 wt%) prepared by induction melting of pure metals and hot rolled into strips of 0.5 mm thickness were ...thermally processed by using three different heat treatments: direct quenching, step-quenching and up-quenching with boiling water and room temperature water as the quenchants. The effects of composition and different methods of heat treatment on the microstructure and transformation temperatures of the investigated Cu-Zn-Al alloys were investigated using SEM-EDS and DSC techniques.
•Thermodynamics of the metal alloys.•CALPHAD method and optimized thermodynamic parameters for calculation of alloys properties.•Microstructure of Cu-rich region of the Cu–Al–Ag system using scanning ...electron microscopy with energy dispersive X-ray spectroscopy.
Copper rich region in shape memory Cu–Al–Ag system was experimentally investigated using DTA and calculated using optimized thermodynamic parameters according to CALPHAD method. Overall composition alloys were chosen along three vertical sections with constant copper content of 70, 80 and 90at%. Experimentally determined solidus and liquidus temperatures were compared with the results of thermodynamic calculation and good mutual agreement was noticed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Although the European Union's directive about environment protection as WEEE and RoHS have been carried out in 2003, led solders are still in used in Serbia. In the aim to respect the European and ...world directives and laws, it is necessary to reduce a quantity of toxic element and to establish lead and cadmium free solders in production. In this paper it was presented lead-free alloys, which are used for ecological solders manufacturing and various applications.
The influence of Ag addition on microstructure and thermal properties of the Cu-10%Al–8%Mn alloy was investigated in this work. Two alloys with designed compositions Cu-10%Al–8%Mn and ...Cu-10%Al–8%Mn-4%Ag (in wt.%) were prepared by induction melting of pure metals. Microstructures of the prepared samples were investigated in the as-cast state, after homogenization annealing and after quenching. The effects of different methods of heat treatment on the microstructure and transformation temperatures of the investigated Cu-10%Al–8%Mn and Cu-10%Al–8%Mn-4%Ag alloys were investigated using SEM-EDS and DSC techniques.It was determined that after induction melting microstructure of the both investigated alloys are primarily composed of martensite and a small amount of α-phase precipitates.Fully martensitic structure in both investigated alloys was obtained after direct quenching from the 850 °C into the ice water. Based on the DSC cooling curves it was determined that two-step martensite transformation for the both investigated alloys occur in the temperature interval from about 30 to -40 °C.
Phase equilibria in the Bi–Cu–Ni ternary system have been studied using differential thermal analysis (DTA) as well as by using the calculation of the phase diagram (CALPHAD) method. Literature ...experimental phase equilibria data and DTA results from this study were used for thermodynamic modeling of the Bi–Cu–Ni ternary system. Isothermal sections at 300, 400, and 500 °C, vertical sections from bismuth corner with molar ratio Cu:Ni=1/3, 1/1 and 3/1 and vertical section at 40 at.% Cu were calculated and compared with corresponding experimental results. Reasonable agreement between the calculated and experimental data was observed in all cases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Phase transition temperatures of the selected samples with compositions along isopleths: GaSb–AuGa2, GaSb–AuGa, Au–GaSb, Sb–AuGa, GaSb–Au0.3333Sb0.6667 and Ga–Au0.5Sb0.5 were measured using ...differential scanning calorimetry (DSC). Experimentally determined phase transition temperatures were compared with the results of thermodynamic calculation. Also, predicted phase equilibria at room temperature were compared with the literature experimental data.
► Au–Ga–Sb phase diagram was investigated using DSC and thermodynamic prediction. ► GaSb–AuGa2 and GaSb–AuGa sections were determined as simple quasibinary eutectic systems. ► Liquidus surface temperatures and four invariant reactions were obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
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![[P119] Thermal Analysis of ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0364-5916/small "[P119] Thermal Analysis of the Alloys in Copper Rich Region of Cu-Al-Ag System")
