Quantitative assessment of the microstructural factors controlling the fatigue crack initiation mechanisms in AZ31 Mg alloy

Quantitative investigation on the deformation modes and cracking behavior during cyclic torsional loading of extruded pure Mg and Mg‐3Y alloy

“…Therefore, the wide range of θ for the activation of pyramidal slip, as demonstrated in Figure 9D, is possibly responsible for the enhanced activity during cyclic torsional deformation. Similar results for high activity of nonbasal slip under torsional loading were also reported in earlier works 17, 26 …”

“…Fatigue failure due to the initiation and propagation of cracks is one of the most important reasons for damage to structural components. [25][26][27] Thus, revealing cracking modes in Mg alloys is of significant value. 9,10,22,23,28 Yue et al 28 studied the high-cycle fatigue behavior of Mg-3.0Nd-0.2Zn-Zr alloy at RT and concluded that there were two typical cracking modes: persistent slip band (PSB)-induced cracking caused by the accumulation of slip-associated strain localization and tension twinning (TTW)-induced cracking caused by TTW.…”

“…Fatigue failure due to the initiation and propagation of cracks is one of the most important reasons for damage to structural components 25–27 . Thus, revealing cracking modes in Mg alloys is of significant value 9,10,22,23,28 .…”

“…They found that the cracking modes were closely related to the deformation modes during cyclic loading. Jamali et al 26 studied deformation modes and fatigue cracking nucleation mechanisms in AZ31B alloy during low‐cycle fatigue at different cyclic strain semi‐amplitudes (Δε 1 /2 = 0.4%, Δε 2 /2 = 2.0%). The most damaging fatigue cracks were nucleated along twins in large grains, coupled with cracks parallel to basal slip bands with the deformation localization in clusters of small grains favorably oriented for basal slip at a low cyclic strain semi‐amplitude.…”

Quantitative study on the influence of strain amplitude on deformation mechanisms and cracking modes during cyclic torsion of AZ31 magnesium alloy

“…Furthermore, cracking modes after fatigue failure of Mg alloys also show a high dependency on strain amplitude. [31][32][33][34] For example, Wang et al 32 found the microcracks of the GW83 sheets after tensioncompression fatigue failure were preferentially initiated at grain boundaries (GBs) and intergranularly propagated at 1.2% strain amplitude while cracks were mainly initiated at slip traces (ST) and the crack growth is primarily transgranular at 0.5% strain amplitude. They suggested the higher activity of dislocation slip at higher strain amplitude would promote the coalescence of cracks to form long intergranular cracks.…”