Initial precipitation and hardening mechanism during non-isothermal aging in an Al–Mg–Si–Cu 6005A alloy

摘要: Abstract The characterization of precipitation and hardening mechanism during non-isothermal aging had been investigated using high resolution transmission electron microscopy for an Al–Mg–Si–Cu 6005A alloy. It was proposed that the needle-shaped β″ precipitates with a three-dimension coherency strain-field increased number density in Al matrix provided maximum strengthening effect Simultaneously, it also found formation evolution clusters early were associated vacancy binding energy, which Si atoms played important role controlling numbers Mg/Si co-clusters, excess nucleation sites subsequent to strengthen improve rate. Finally, based on experimental observation theoretical analysis, sequence alloy as: supersaturated solid solution → Si-vacancy pairs, Mg-vacancy pairs Mg clusters → Si clusters, dissolution clusters → Mg diffusion into existing clusters → Mg/Si co-clusters → GP zone.