Wrought magnesium alloys, such as AZ31B, typically develop strong texture during processing as a consequence of high plastic anisotropy, leading to poor ballistic performance. In an effort to improve the impact performance, a novel pretwinning process was developed in rolled AZ31B plates. Here, the rolled plate was cut into 3” cubes. The cubes were subsequently pre-compressed along the transverse and rolling directions to introduce pretwins. Individual plates were cut from the cubes and impacted with 0.30 cal fragment simulating projectiles. The pretwinned samples showed a 15% improvement the velocity required to penetrate the samples, or V50, compared with reference samples. In addition, back face spalling was effectively suppressed by the introduction of pretwins. This improvement to the ballistic performance was achieved without modifying the hardness. To understand the origins of the enhanced ballistic performance the microstructure was characterized by a combination of electron backscattered diffraction and x-ray diffraction. Changes in strength and ductility along different orientations were further assessed via shear punch testing.
2021-04-07 08:00:00
