3.3. Fracture behavior of as-cast M

3.3. Fracture behavior of as-cast Mg-10Li-5Zn-xEr alloysFig. 9 shows the tensile fracture of the studied alloys. Fig. 9a is the fracture image of LZ105 alloy which demonstrates some dimples and several cleavage planes. And appropriate Er addition makes the dimples in the fracture morphology more and deeper which is in accordance with elongation of the studied alloys as shown in Fig. 9. In general, bigger and deeper dimples can accommodate large strain which results in higher EL. There are none particles in dimples of LZ105 alloy. However, several particles shown inside the circles labeled in Fig. 9 can be observed in dimples of LZ105-xEr alloys. The size and the number of these particles become larger with increase of Er content. Through the XRD, TEM and SEM analysis mentioned above, Er addition leads to the formation of W-phase and further Er addition results in more and coarser W-phase. It can be concluded that these particles in dimples are mainly W-phase and bulky W-phase may be the fracture origin during the tensile testing.