Welding Metallurgy of

Effect of the second phases on corrosion behavior of the Mg-Al-Zn alloys

Investigation on microstructure and mechanical properties of Al-Zn-Mg-Cu alloys with various Zn/Mg ratios

The 5xxx series (Al-Mg-based) aluminum alloys suffer from intergranular corrosion and intergranular stress corrosion cracking when the alloy has become “sensitized.” Sensitization refers to insidious precipitation of β phase (Mg2Al3), which is problematic when present at grain boundaries. The β phase is electrochemically active and may preferentially dissolve. This paper reviews the relevant works that have documented the degree of sensitization for various 5xxx series alloys, providing a holistic overview of the issue, along with attention to the bulk composition, heat treatment, and microstructure.

A Survey of Sensitization in 5xxx Series Aluminum Alloys

Mechanical properties, intergranular corrosion behavior and microstructure of Zn modified Al–Mg alloys

Correlations between stress corrosion cracking, grain boundary precipitates and Zn content of Al–Mg–Zn alloys

The precipitation hardening behavior of Al–5.1Mg–0.15Cu alloy with 3.0Zn (wt%) addition at various temperatures has been systematically investigated in this study. The Al–5.1Mg–0.15Cu–3.0Zn alloy possesses the higher strength compared with traditional Zn-free alloy, when the alloy is treated at 363 K for 24 h and subsequently aged at 413 K for 25 h. The precipitation sequence of the hardening phase T-Mg32(AlZn)49 is investigated by differential scanning calorimetry tests, transmission electron microscopy and high-resolution electron microscopy. The different effects of natural aging and pre-aging on the precipitation hardening behavior are detailed. The formation of relatively stable Guinier–Preston zones of T-Mg32(AlZn)49 phase during pre-aging rather than natural aging results in higher mechanical strength during subsequent artificial aging at relatively high temperatures. When the Al–5.1Mg–0.15Cu–3.0Zn alloy is aged at 453 K, the peak hardness is from synergetic effect of hardening of S-Al2CuMg phase and coarsening of T phase. However, during two-step artificial aging treatment, the peak hardness results from fine, spherical and homogeneously distributed T phase in the absence of the S phase.

Di Zhang

Papers

Mechanical properties, intergranular corrosion behavior and microstructure of Zn modified Al–Mg alloys

Correlations between stress corrosion cracking, grain boundary precipitates and Zn content of Al–Mg–Zn alloys

Precipitation hardening behavior and microstructure evolution of Al–5.1 Mg–0.15Cu alloy with 3.0Zn (wt%) addition

Improved age-hardening response and altered precipitation behavior of Al-5.2Mg-0.45Cu-2.0Zn (wt%) alloy with pre-aging treatment

Effects of Cu addition on the precipitation hardening response and intergranular corrosion of Al-5.2Mg-2.0Zn (wt.%) alloy