[Chinese aluminum industry website] aluminum alloy intercrystalline corrosion {UheJnnl}ngJ-onfush- aluminum alloy intergranular corrosion (intergranul.: corr () Sionofaluminiumalloy) in the aluminum alloy grain boundaries Bu shengyou corrosion is aluminum alloy The form of corrosion. The mechanism is the role of electrochemistry, which is the result of the action of the local cells. Intergranular corrosion is the common form of corrosion in aluminum alloys in copper-containing aluminum alloys, as an intermetallic compound for the strengthening phase. (CuAI:) phase and S (euMgAI:) are equal (see the phase of the aluminum alloy) and the cathode is relative to the aluminum substrate. In the aluminum-magnesium-based alloy, the intermetallic compound is an Mg5A18) phase and is an anode with respect to the aluminum matrix. When these intermetallic compounds are continuously distributed in the grain boundary to form a network, intergranular corrosion occurs due to micro-cell corrosion between the grains and grain boundaries, compounds and grain boundaries. The sensitivity of intergranular corrosion of aluminum alloys depends mainly on the alloy composition and heat treatment, and is also closely related to the corrosion environment. In order to reduce the sensitivity of the intergranular corrosion, the precipitation phase can be distributed in a uniform and dry state by heat treatment, or the precipitation phase can be controlled. Such as high-strength hard alloy alloy aging process is in the GP zone (see aluminum alloy aging), no precipitation phase. In addition, limiting the content of alloy components can also inhibit the formation of precipitated phases.
Vickers hardness, room temperature stretching, polarization curve testing, and intergranular corrosion, exfoliation corrosion tests, etc., combined with metallographic (OM) and transmission electron microscopy (TEM) analyses, were used to study the Regression and Re-ageing (RRA) process for aluminum 1973. Alloy mechanical properties and intergranular corrosion and spalling corrosion. The results show that the intergranular corrosion and exfoliation corrosion tendency of 1973 aluminum alloy after different aging treatments are the same. The order of RRA corrosion resistance from large to small is: 200°C, 60min, 180°C, 60min, 180°C, 40min; 180 °C, 20min; T6. RRA180°C treatment for a suitable amount of time can increase the strength and resistance to intergranular corrosion and exfoliation corrosion of 1973 aluminum alloy, and with the increase of regression time, the corrosion resistance increases, but the strength decreases. The RRA 200 °C, 60min treatment and 180 °C treatment, although there is better corrosion resistance, but the strength loss is too large. Therefore, the 1973 aluminum alloy has better comprehensive performance after being treated at RRA 180°C for 60 min.
