Homogenization Modes Effect on Mechanical Properties and Corrosive Characteristics of the Rolled Products from Al-Mg (1570) Aluminum Alloy with Addition of Scandium and Zirconium

Abstract

Objective of the study: study of various homogenization modes effects on mechanical and corrosive properties of rolled sheets from Al-Mg system alloy 1570 with additions of zirconium and scandium transition metals. The sheets were produced in laboratory conditions from the ingot, cast in production DC mold based on the commercial production practices and treatment modes. 4 homogenization modes, 2 tempers H12 and H321, and several modes of stabilization annealing in the temperature range from 240 °C to 325 °C have been reviewed. The samples have been comprehensively examined using optic and electron scanning microscope, mechanical properties were achieved by break test in compliance with ISO 6892-1, corrosion was examined using ASTM G66 and G67 standards. The curve of 1570 alloy sheets softening as the function of annealing temperature was constructed. It was demonstrated that the increasing temperature effect during homogenization leads to strength properties decrease and corrosion resistance improvement due to interdendritic segregation elimination. Among analyzed homogenization modes, 360 - 380 °C - 6 h mode is established as the most practical, and the sheets. produced without stabilization annealing, occurred to be the most resistant to exfoliation corrosion. The sheets, subjected to annealing at 260 °C - 2 h, show no traces of layer corrosion, but have pit corrosion locations rated as «PC» based on ASTM G-66 classification, such rating is unacceptable for the manufacture of products for use in the marine environment.