Effects of AlN reinforcement particles on the twinning nucleation and growth in AZ91 alloy

In-situ AlN particles of only 1.5 vol. % induced the twins number increment of about 67 % in AlN/AZ91 composites, which confirmed that AlN particles were more efficient than the Mg₁₇Al₁₂ precipitates on twinning nucleation. The experimental observation further revealed that AlN particles could inhibit the growth of extension twins by bowing the twinning dislocations around them, which provided an additional driving force for twinning nucleation. In addition, the theoretical calculation results demonstrated the increased twin number in AlN/AZ91 composites was mainly attributed to the inhibition of AlN particles on twinning growth.