Heat treatment enhancing the hydraulic fracturing performances of Al-Cu-Ga-In-Sn alloys

Abstract

For improving the mechanical properties of Al-Ga-In-Sn alloys used to make dissolvable hydraulic fracturing tools, the effects of Cu and heat treatment on the microstructures and the Al-water reactivities of Alloys with Cu addition were investigated. The XRD and SEM were employed to investigate their microstructures. When the Cu content of alloys is above 1 wt%, Cu can dissolve in Al grains and form CuAl2 phases at Al grain boundaries, which can strengthen Al-Cu-Ga-In-Sn alloys. Cu will not form intermetallic compounds with Ga, In, and Sn, so liquid GIS phases are still observed at Al grain boundaries. The Cu and Ga atoms can diffuse from CuAl2 and GIS phases to Al grains during solution treatment. The CuAl2 phases can precipitate in Al grains during the artificial aging treatment of alloys. The increment of Cu, and Ga contents of Al grains, and the formed CuAl2 precipitates in Al grains will further strengthen the heat treatment alloys. Al-water reactivities of as-cast and heat treatment alloys were performed in different water temperatures. The solute Cu in Al grains and CuAl2 phases at Al grain boundaries will occupy the contacting sites for Al reacting with water, leading to H2 generation rates and H2 yield of reactivity of Cu-bearing alloys with water decreasing. After heat treatment, the increment of Cu content and CuAl2 precipitates in Al grains will occupy more contacting sites for Al reacting with water, resulting in a lower H2 yield of Al-water reaction of heat treatment alloys than that of as-cast alloys.