Fabrication of AZ31/Mg3Y Composites with Excellent Strength and Plasticity via Accumulated Rolling Bonding and Diffusion Annealing

AZ31/Mg3Y composites with a layer thickness of 100-200μm were fabricated by accumulated rolling bonding(ARB),which was followed by diffusion annealing at 300℃ for 0-32 h.An interface layer,containing numerous Al-Y precipitates,is formed in the Mg3Y layer that is adjacent to the interface as a result of Al diffusing from the AZ31 layers into the Mg3Y layers.The thickness of the interface layer gets increased and more precipitates are formed in the interface layer with the extension of the annealing time.The microhardness of the AZ31 and Mg3Y layer decreases firstly and then reaches a stable value,while the microhardness of the interface layer increases gradually with the extension of the annealing time.The AZ31/Mg3Y composites exhibit equivalent strength but increased ductility after diffusion annealing,in comparison to the as-rolled AZ31/Mg3Y composite.In addition,the AZ31/Mg3Y composites after annealing always present higher strength and ductility than AZ31/AZ31 composite,which was fabricated by the same process as that for the AZ31/Mg3Y composites.Hetero-deformation induced strengthening also plays an important role in the excellent strength and ductility of the annealed AZ31/Mg3Y composite.This study can provide a direction for improving the plasticity and strength of magnesium alloys synergistically.

Improvement of the matrix and the interface quality of a Cu/Al composite by the MARB process

The matrix accumulative roll bonding technology （MARB） can improve the matrix performance of metal composite and strengthen the bonding quality of the interface./n this research, for the fwst time, the technology of MARB was proposed. A sound Cu/AI bonding composite was obtained using the MARB process and the bonding characteristic of the interface was studied using scanning electricity microscope （SEM） and energy-dispersive spectroscopy （EDS）. The result indicated that accumulation cycles and diffusion annealing temperature were the most important factors for fabricating a Cu/AI composite material. The substrate aluminum was strengthened by MARB, and a high quality Cu/AI composite with sound interface was obtained as well.

退火温度对Mg/Al轧制复合层组织和性能影响

采用扫描电镜(SEM)、光学显微镜(OM)、拉伸实验机、X射线衍射仪(XRD)等研究了退火温度(220~380℃)对MgAZ31和Al(1A99)轧制复合层的微观组织结构、力学性能、拉伸断口的形貌及物相成分影响。结果表明:随着退火温度的升高,镁、铝原子逐渐进行扩散迁移,扩散层厚度增加,从220℃时的1.80μm逐渐增加到380℃时的45.10μm,且扩散层的生长速率逐渐增大;当退火温度达到300℃时,断口处出现密集的韧窝,镁基体的断裂形式向塑性断裂转变,镁基体的塑性增强,断口的物相为Mg_(2)Al_(3)相,抗拉强度达到最大,为272.35 MPa,此时试件的综合力学性能达到最佳,故300℃为最佳退火温度。

不锈钢/碳钢冷轧复合机理的研究

通过对不锈钢 碳钢复合板冷轧工艺的研究 ,提出了不锈钢 碳钢冷轧复合的结合机理。分析了影响不锈钢与碳钢复合的主要因素 ,指出扩散退火可以明显提高复合界面的结合性能。得到的实验数据对于开发新的不锈钢 碳钢复合板冷轧工艺有指导作用。

冷轧铝-铝复合材料的扩散退火行为研究

对铝铝复合材料的扩散退火行为进行了研究，实验结果表明，提高复合材料结合强度的退火温度为２００℃或６００℃左右。结合生产实际，最佳扩散退火工艺的参数为（６００±２０）℃×１ｈ。

扩散退火和热轧温度对钛铜界面结合强度的影响

对热挤压的钛铜复合棒进行扩散处理,研究扩散退火温度及保温时间对界面结合强度的影响,并通过测试Ti和Cu在高温下的拉伸性能来选择较为合适的热轧温度。结果表明:扩散退火可有效促进界面处金属原子的扩散和增强结合强度,当扩散退火在780~800℃/30 min时复合界面的结合强度最高;钛铜复合棒热轧温度应选择780℃较为合适,此时Ti、Cu的强度和塑性指标相近,利于热轧时的均匀变形;钛铜复合棒的热轧结合机理可用N. Bay理论、热作用机制及位错学说进行解释。