Heating aging behavior of Al–8.35Zn–2.5Mg–2.25Cu alloy

A novel constitutive model for multi-step stress relaxation ageing of a pre-strained 7xxx series alloy

“…These precipitates are large enough to provide high dislocation cutting strength, while being appropriately small to avoid the dislocation bowing (softening) phenomenon (Polmear, 2005), thus exhibiting high resistance to dislocation motion. The finding is similar to most of the literatures that studied the precipitate evolution of 7xxx serious alloys (Dumont et al, 2003;Liu et al, 2014;Sha and Cerezo, 2004;Stiller et al, 1999;Werenskiold et al, 2000;Zang et al, 2012). With the ageing time continuing to increase, the material will achieve the peak aged state, where all elements are assumed depleted and occupied by the precipitates, and further, coarsen to realise the T74 over-aged states.…”

“…Figure 2 (b)), growth (Figure 2 (b)→(c)) and coarsening (Figure 2 (c)→(d)), is clearly observed. Figure 3 (a) Schematic illustration of age-hardening mechanism and (b) evolutions of precipitate radius (Dumont et al, 2003;Liu et al, 2014;Sha and Cerezo, 2004;Stiller et al, 1999;Werenskiold et al, 2000;Zang et al, 2012), r, density (Sha and Cerezo, 2004;Stiller et al, 1999), d, volume fraction (Han et al, 2011), f, during T74 ageing treatment A schematic illustration is provided in Figure 3 to facilitate the understanding and calibration of the evolution of the internal variables during the T74 ageing treatment. The original state of the materials is a supersaturated solid solution (SSSS) in preparation for the subsequent ageing treatment (Poole, 1997).…”

“…The equations were first verified by an experimentally observed multi-step stress relaxation ageing behaviour with different initial stresses (Zheng et al, 2018). To aid the micro-internal variable calibration in this model, both the TEM results, and the values of precipitate radius and volume fraction under similar pure ageing conditions (Dumont et al, 2003;Han et al, 2011;Liu et al, 2014;Sha and Cerezo, 2004;Stiller et al, 1999;Werenskiold et al, 2000;Zang et al, 2012) were employed. These equations were further applied to the multi-step stress relaxation ageing behaviour after different pre-strain levels.…”

Microstructure and Mechanical Properties of 45 vol.% SiCp/7075Al Composite

“…3(b) and (c)). It indicates that the main precipitates in Al matrix after aging treatments were h 0 phases, which has been widely reported to be semi-coherent with Al matrix [29,30] .…”

Effects of non‐isothermal aging process on mechanical properties and corrosion resistance of Al–Mg–Si aluminum alloy

“…Recently, the effect of the non‐isothermal aging on microstructure and mechanical properties of Al–Zn–Mg–Cu alloy was studied by non‐isothermal aging treatment to settle the problem of inconsistent temperature at inside and outside of the large component of aluminum alloy . Also, it has been found that through the linear heating and the combination of heating and cooling process of non‐isothermal aging were capable of obtaining higher mechanical properties and comparable corrosion resistance for the Al–Zn–Mg–Cu alloy .…”