Influence of cooling rate on the formation of the primary structure of deformable aluminum alloys

Abstract

Today, in the world, it is widely used in the production of aerospace equipment, sea vessels, railway transport and cars have high-strength aluminum alloys Al-Zn-Mg-Cu (for example, B95) and alloys of medium Al-Mg (AMg5), Al-Si-Mg ( AD35) and increased strength Al-Cu-Mg (D16). An in-depth study of individual factors that directly affect the structure of the work piece can be crucial for improving product quality during further thermomechanical processing. The article defines data on the grain size of the primary phase of aluminum alloys depending on the cooling rate of castings of various aluminum alloys (AD35, B95, D16, AMg5). It is shown that an increase in the cooling rate from 2-8 ° C / s to almost 1000 ° C / s leads to a decrease in the grain size of the фазы-phase from 200 μm to 10-40 μm. As a result of the experiments carried out in the work, the intervals of hardening of the investigated aluminum alloys were determined. It is shown that aluminum alloys containing copper in the chemical composition (≥1%) have a significantly wider crystallization range, in particular, B95 (1600C) and D16 ( 1320C). The samples of strip used in this work from high-strength aluminum alloys obtained by roll casting, to expand the range of investigated cooling rates, have a homogeneous structure with a uniform distribution of phase components, which ensures high functional properties of rolled products from high-strength, heat-strengthened alloys of the Al-Cu and AL-Zn systems. The obtained data of the research results can be recommended for use in the development of the domestic technology of roll casting of high-strength aluminum alloys. Keywords: High-strength aluminum alloys, roll casting, cooling rate, solidification time, differential thermal analysis, grain size.