不同取样方向对AZ31镁合金高周疲劳性能的影响
谭 力，张喜燕*，尹瑞森，余江平，舒 洋，刘 庆不同取样方向对AZ31镁合金高周疲劳性能的影响
谭 力，张喜燕*，尹瑞森，余江平，舒 洋，刘 庆
（重庆大学 材料科学与工程学院，重庆400030）
摘 要 在轧制镁板材沿TD和RD方向分别切取疲劳试样，并对它们进行室温下的高温疲劳变形。EBSD分析方法应用于样品的微观组织及织构变化的表征方面。发现经高周应力疲劳变形后，由于应变量非常小，RD与TD方向整体孪晶数量都不多，疲劳后相比疲劳前孪生体积分数有所增加，沿TD方向的孪生体积分数高于RD方向。经拉压循环变形后除｛10-12｝拉伸孪生外还出现了少量的｛10-11｝压缩孪生与｛10-11｝-｛10-12｝二次孪生，导致屈服强度增加，TD方向的抗拉强度与延伸率均高于RD方向。分析其断口形貌发现TD方向疲劳辉纹较小，解理断裂的区域更少，韧窝比较深，故TD试样的高周疲劳性能以及材料的塑性略优于RD试样。由于轧制织构在轧制面内基本对称，所以二者的差别并不太显著。
关键词 AZ31；高周疲劳；EBSD；孪晶；断口
中图分类号：TG115.5+7;TG146.2+2;TG115.21+3;TG115.23 文献标识码：A doi:10.3969/j.issn.1000-6281.2016.01.004
The impact on properties of AZ31 magnesium alloy in different direction during high cycle fatigue process
TAN Li，ZHANG Xi-yan*，YIN Rui-sen，YU Jiang-ping，SHU Yang，LIU Qing
（School of Material Science and Engineering，Chongqing University，Chongqing 400030，China）
Abstract Samples for high cycle fatigue deformation at room temperature were cut from the hot-rolled AZ31 sheet along the rolling direction(RD) and transverse direction (TD). The electron backscatter diffraction technique(EBSD) was used to investigate the microstructure and texture evolution. Due to the strain is much lower, there are little twins generated during the high cycle deformation in both directions, but the volumes fraction of the twins increased after fatigue deformation, and the sample of transverse direction had larger numbers of twins than the rolling direction. After tension-compression cyclic deformation, both {10-12}tension twin, a few compression twinning{10-11}and secondary twinning {10-11}-{10-12} were generated, cause the yield stress reduced. Analyze the fracture of the samples, it was found that in Rd samples, the larger area of fatigue striations, the more cleavage fracture and the shallower dimples than TD samples. The result shows that both the fatigue strength and elongation of the TD samples are higher than those of the RD samples. Because of the rolling texture is symmetric in the rolling plane, the difference is not significant.
Keywords AZ31；high cycle fatigue；EBSD；twin；fracture
全文下载请到同方知网、万方数据或重庆维普等数据库中下载！