Effect of Re addition on the crystallization, heat treatment and structure of the Cu–Ni–Si-Cr alloy

Abstract

For determination of the structure and properties of those alloys, the following investigations were carried out: scanning microscopy and EDS X-ray analysis. Investigations concerning the optimal chemical composition and production method of Cu-Ni-Si alloys modified by Cr and Re as well as the improved properties in comparison with traditional alloys contribute to better understanding of mechanisms influencing the improvement of mechanical properties of the newly developed alloys. Thermal analysis of the crystallization process allows for accurate calculation of latent heat of various phases developed during solidification. Based on the assumption that the latent crystallization heat is proportional to the share of various phases in the alloy, the thermo-derivative analysis also allows the calculation of the amount of crystallized phases. Calculation of the properties as mentioned earlier is based on the characteristic points determined in a derivative curve. The adequately selected chemical composition of the alloy, as well as the appropriate cooling rate and heat treatment conditions, leads to improvement of functional properties of manufactured elements. For the analysed alloys, a thermal derivative analysis was used to determine the kinetics of crystallization and the temperature of the beginning and the end of a phase and eutectic crystallization, mainly the liquidus temperature (T L) and solidus temperature (T SOL). The T SOL temperature determined on thermal derivative analysis is the upper limit of supersaturation of the tested alloys. The conductivity and microhardness of the tested alloys were also measured in the function of the chemical composition and the state (i.e., heat treatment).

Precipitation Strengthening of Cu–Ni–Si Alloy

“…These requirements apply to the whole spectrum of properties at the same time. Modern materials are expected to be both durable and reliable during operation, and thus have good strength, electrical and thermal properties [1][2][3][4].…”

“…In the obtained Cu-Ni-Si-Cr, Cu-Ni-Si-Cr-Mg or Cu-Ni-Si-Cr-Ti alloys, the results of investigations indicate a change in morphology, resulting in more beneficial mechanical properties and in some cases also beneficial changes in conductivity. It is known that very often during heat or plastic treatment, strength properties are enhanced, but electrical properties deteriorate [3][4][5][6][7][8][9][10][11].…”

“…The analysis and investigations of Cu-2Ni-1Si alloy modified with Cr, Ag [2] as well as the investigations and results of our own research and the development of science and increasing demands have acted as the basis for the investigation of Cu-2Ni-1Si alloys modified with rhenium. Re content was determined at the level below 1% due to scarce resources and the results obtained for Cu-2Ni-1Si-0.8Cr alloys modified with rhenium [3].…”

“…Structure of Cu-2Ni-1Si alloy modified with Re: dark field image (a), diffraction pattern of the zone axis for[1][2][3][4][5][6][7][8][9][10][11] Re (b).…”

The Influence of Ag on the Microstructure and Properties of Cu-Ni-Si Alloys

“…The drive for industrial advancement and new technologies forces the development of materials engineering and the continuous improvement of existing materials, as well as the development of completely new classes of high-quality materials [ 1 , 2 , 3 , 4 ]. Operational durability and reliability are a priority and drive the search for materials with more favorable and precise sets of features, such as high and stable mechanical, electrical, and/or thermal properties during operation.…”