Metals obtain optimum conditions of metallurgical and physical properties through a heat treatment. Brass is one of the copper alloys which has many applications in everyday life and in the industry. Brass is one of the copper alloys which has many applications in everyday life and the industry. In this work, the influence of the precipitation heat treatment temperature on the metallurgical microstructure, structure, thermal properties, and microhardness of an alpha brass is analyzed. Samples were heat treated by precipitation for 2 h at 300˚C, 400˚C, 500˚C, 600˚C, and 700˚C. The best mechanical properties were found at 500˚C of precipitation heat treatment temperature. Specimens were characterized by scanning electron microscopy, X-ray diffraction, Vickers microhardness, photothermal radiometry, and photoacoustic to study the thermal diffusivity and conductivity, as well as the heat capacity. The inverse of the full width at the half maximum analysis showed that the crystallinity decreased as the precipitation heat treatment temperature increased. Metallurgical microstructure and microhardness were correlated to the precipitation heat treatment temperatures to determine the effect on the metallurgical and mechanical properties, as well as the effect on the thermal properties of alpha brass. How to cite this paper: Rojas-Rodríguez, I., Lara-Guevara, A., Salazar-Sicacha, M., Mosquera-Mosquera, J.C., Robles-Agudo, M., Ramirez-Gutierrez, C. and Rodríguez-García, M. (2018) The Influence of the Precipitation Heat Treatment Temperature on the Metallurgical, Microstructure, Thermal Properties, and Microhardness of an Alpha Brass. Materials Sciences and Applications,9,[440][441][442][443][444][445][446][447][448][449][450][451][452][453][454]

Abstract

In this text, a numerical model using the finite element method (FEM) is developed to describe absorption phenomena using the Beer-Lambert law. Numerical results are compared against experimental measurements made on alpha brass, characterized by photothermal radiometry (PTR). Results from the numerical analysis are in good agreement with the measurements obtained from the radiometry tests. In this technique the material is subjected to a laser heating, producing a thermal wave that is captured with a detector by means of the amplitude and phase parameters. The analysis of the data obtained from six samples provides information about their thermal properties, such as conductivity and diffusivity, which can be correlated with structural changes in a material. Results from this research lead to the characterization of mechanical properties of metallic materials.

Different investigations of the union of dissimilar materials such as stainless steel and different castings have been carried out, but rapid cooling immediately after welding has not been considered, in this work it was investigated how rapid cooling affects the metallurgical microstructure and consequently the mechanical properties. The effect of welding parameters on the microstructure and mechanical properties of the joint between dissimilar metals, an E-308-16 austenitic stainless steel and Gray Cast Iron was also analyzed. Gray cast iron samples (GCI) were fabricated, welded and cooled. The main welding parameters studied in this work are the welding technique and the type of filler electrodes. Flux-coated electrode E-308-16 was applied for this different joint. An experimental study was carried out for the analysis of welded joints of similar and dissimilar steels. The microstructure of the welded joints was analyzed using an optical microscope, in the base metals, heat affected zone (HAZ) and filler metal. The mechanical properties of the welded joints were evaluated by Vickers microhardness and tensile strength tests. The hardness profile showed differences in hardness between the base metals, the heat affected zone and the filler metal. The metallurgical microstructures observed along the welded areas corresponded to the profile. The hardness differences determined the effect on the mechanical and metallurgical characteristics of the welded samples as a result of the cooling rate differences. This research work is important because it allows us to analyze the possibility of reworking pieces of dissimilar materials by welding or, failing that, to determine if this may or may not be possible.