钪锆元素对3102铝合金圆管微观组织稳定性的影响

采用多尺度微观组织表征方法研究钪锆微合金化对3102铝合金铸造、时效、热挤压和预变形及退火过程中的微观组织演化以及对挤出圆管力学性能的影响。结果表明:钪锆微合金化促使合金在铸造时发生非均质形核,显著细化合金的铸造组织;含钪锆合金在时效后,组织中析出高密度的纳米级Al3(ScxZr1−x)相;析出相不仅抑制了合金在热挤压过程中的再结晶行为,而且在随后的预变形及退火过程中起到抑制再结晶、钉扎晶界和保留纤维组织的作用。添加0.24%Sc和0.23%Zr(质量分数)元素使得挤出圆管屈服强度由26 MPa提升至89 MPa,抗拉强度由70 MPa提升至122 MPa。不含钪锆的3102合金圆管在8%预变形、600℃退火后,组织中出现晶粒异常长大;添加钪锆元素后,组织中的异常长大行为被抑制。钪锆元素增强3102铝合金的再结晶抑阻,提升合金在预变形及退火过程中的组织稳定性。

3xxx铝合金微通道扁管晶粒组织和加工硬化

采用电子背散射衍射技术,研究了分别使用两种铝合金(3102和3F03)制备的同规格微通道扁管的晶粒组织,比较了5%冷轧变形后两种铝扁管中的残余应变分布。对冷轧后的铝扁管进行600℃/3 min退火处理,获得了包含异常大晶粒的退火组织。基于铝扁管的单向拉伸实验数据和加工硬化率曲线,建立了含应变修正项的硬化模型。使用该模型对单向拉伸变形过程中铝扁管材料中的位错密度和位错平均自由程演化进行了求解。结果表明:相比于3F03挤压态铝扁管,5%冷轧变形使得3102挤压态铝扁管筋部组织发生较高程度加工硬化;3102挤压态铝扁管在塑性变形过程中的位错平均自由程较小;3102挤压态铝扁管因具有较高的Si元素固溶含量和较小的晶粒尺寸而具有较高的加工硬化率。

Properties and Microstructure of One-Step Cold Rolled Steel Strip for Shadow Mask

The effect of recrystallization annealing temperature on the properties and microstructure of one-step cold rolled steel strip for shadow mask was studied. The results showed that there was no yield point elongation when the tensile tests were performed on the samples for annealing temperatures ranging from 750 ℃ to 810 ℃. Moreover, increasing annealing temperature resulted in large grains, which was beneficial to the formability and magnetic property of steel strips. On the other hand, when the sample was annealed at 840 ℃, its microstructure showed ununiforrnity with 0.04 % yield point elongation, which was not good for the function of the shadow mask. Therefore, the proper recrystallization annealing temperature was about 810 ℃ for the present steel strip for shadow mask.