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通过采用连续弯曲(CB)工艺来改善AZ31镁合金板材的成形性能。通过光学显微镜(OM)和电子背散射技术(EBSD)研究镁合金板材的显微组织和织构的变化。结果表明:经过CB处理并退火后基面织构强度明显削弱;第一道次弯曲在内表面产生大量的孪晶,由于在第二道次过程中发生退孪生,孪晶密度明显下降;由于V形弯曲时内侧和外侧拉压应变状态的不对称性,连续弯曲过程中孪生-退孪生交替出现;与原始板材相比,经过连续弯曲处理板材的杯突值为5.2 mm,提高了41%,这主要是由于基面织构的弱化,以及织构弱化导致的较小的塑性应变比(r值)和较大的加工硬化指数(n值)。
The forming properties of AZ31 magnesium alloy sheet are improved by using continuous bending (CB) process. The changes of microstructure and texture of magnesium alloy sheet were studied by optical microscope (OM) and electron backscattering (EBSD). The results show that the texture strength of the base surface is significantly weakened after CB treatment and annealing. The first pass produces a large number of twins on the inner surface, and the twins densities drop obviously due to the de-twinning during the second pass. Asymmetric tensile stress and strain state of the medial and lateral V-shaped bending, twins - degenerate twin alternately appear during the continuous bending process; Compared with the original plate, the bending value of the plate after continuous bending is 5.2 mm, increased by 41% , Mainly due to the weakened texture of the base surface and the smaller plastic strain ratio (r value) and larger work hardening index (n value) due to the weakened texture.