AZ31镁合金轧焊的微观结构和力学性能 - 图文

一个大的冷轧应力也可能是导致微孔和应力集中的原因。据文献[12],这些已有的毛孔凝聚起来,扩大在熔化过程,从而导致区自由反应区低强度和韧性。因此,这是合理的得出这样的结论:冷轧应变应低于10%。更甚的是,基准点中高度集中应力容易诱导裂纹扩展,也有不好的疲劳性能焊缝。然而,如果在焊接后有个适当的热处理这些问题或许可以被解决。

5．结论

摘要本研究结合冷轧和焊接技术算法应用于对AZ31镁合金的目的在于了解对冷轧和静态再结晶在焊接接头的微观结构演化与力学性能的影响。以下的结论,可以得出如下:

(1) 热影响区平均颗粒尺寸随着最

初冷轧应力的增加而减小。冷却变形缺陷的存在能有效抑制热影响区晶粒的生长,由于这样的事实,即能源(热)大部分都被消耗在轧焊样品再结晶核和新晶

入，U 是焊接电压，v 是焊接速度，I 粒的生长上了。 是焊接电流，η是TIG焊的焊接效率(2) 在基准点的加工硬化导致一个（η= 0.90）。在环焊样品中热影响高的微硬度和焊轧样品的UST,区新颗粒产生和双向结晶的消失是和微观硬度的倾向和尺寸晶粒尺观察相一致的。因此，它能总结为在寸的改变相一致。 热影响区的热能主要消耗在轧焊焊接（3） 7%的轧焊样品达到最高的生产过程中再结晶核和新晶粒的生长中。 标本(252 MPa)和强度系数4.2．冷轧和静态再结晶在机械接头性能(87.6%)由于在热影响区的显

的影响很明显随着应变的增长，UTS著晶粒细化。然而,冷轧应变应的增长根据Hall-Petch公式: 低于10%,否则,负面影响如微

孔和应力集中可能放大。

（5） 和 k是常量，d是平均晶粒尺寸，发生在热影响区的裂纹和晶粒尺寸随着冷应变的增长而下降，所以焊接点的拉力也随着冷应变的增长而增长根据Eq。(5)。与文学组做相比较，环焊方法方法极大地改善其焊接强度的加入归功于SRX利用热影响区的热量。这不难理解，轧焊系数比GTAF接头系数低。发生在自由反应区的异常断裂是小裂纹透过空洞发育的结果。基本金属中气体的存在是重要的导致空洞形成的因素[30]。此外，在10%的基本金属中

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