Welding Metallurgy of

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

Giant hardening response in AlMgZn(Cu) alloys

https://pure.unileoben.ac.at/portal/files/5910669/Age_hardening_response_of_AlMgZn_alloys_with_Cu_and_Ag_additions.pdf

Age-hardening response of AlMgZn alloys with Cu and Ag additions

Making sustainable aluminum by recycling scrap: The science of “dirty” 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.

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

The AlMgZn phase (T-phase)-an interesting strengthening phase in precipitation-hardened aluminum alloys has not received sufficient attention and is very different from the commonly studied η-MgZn2 phase. This study focuses on Al-5.1Mg-0.15Cu-xZn alloys with a Zn/Mg ratio below 1.0. This is different from commonly known 7xxx series alloys whose Zn/Mg ratios are above 2.0. The relations among the age-hardening response behavior, clustering of Mg-Zn or Mg-Cu atoms, and precipitation of different hardening phases in Al-5.1Mg-0.15Cu-xZn alloys are investigated via atom probe tomography and transmission electron microscopy. According to the results, the Zn addition stimulates the precipitation of coherent T″ precipitates, but suppresses S-Al2CuMg and β-Al3Mg2 phases. This results in an enhanced and accelerated age-hardening response in alloys with high Zn contents. The 3.0Zn (wt.%) alloy with finer T″ precipitates exhibits the best age-hardening response, followed by the 2.0Zn (wt.%) alloy with T′ precipitates and the 1.0Zn (wt.%) alloy with T precipitates. Clusters with high Mg/(Al + Zn + Cu) ratios cannot act as effective precursors for the transformation of Mg-Zn clusters into T″ precipitates, thereby resulting in a weaker age-hardening response and lower hardness in the 1.0Zn (wt.%) alloy. Furthermore, although T-phases originate from different alloys, their Mg/(Al + Zn + Cu) ratios reach the constant value 3/7 for larger particle sizes. This challenges the chemical composition of traditional equilibrium T precipitates.

Solute clustering and precipitation of Al-5.1Mg-0.15Cu-xZn alloy

The effect of grain boundary character evolution on the intergranular corrosion behavior of advanced Al-Mg-3wt%Zn alloy with Mg variation

Dependence of microstructure, mechanical properties, and inter-granular corrosion behavior of Al-5.1Mg-3.0Zn-0.15Cu alloys with high temperature pre-treatment

The addition of 3 wt-% Zn to the traditional Al–Mg alloy doubled its strength. To understand the strengthening mechanism, the enhancement in strength with the variation in Mg content was studied. T...

Shengli Hou

Papers

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

Solute clustering and precipitation of Al-5.1Mg-0.15Cu-xZn alloy

The effect of grain boundary character evolution on the intergranular corrosion behavior of advanced Al-Mg-3wt%Zn alloy with Mg variation

Dependence of microstructure, mechanical properties, and inter-granular corrosion behavior of Al-5.1Mg-3.0Zn-0.15Cu alloys with high temperature pre-treatment

Strengthening mechanism of age-hardenable Al–xMg–3Zn alloys