【作者】 史杰杰；

【导师】 崔春翔；

【作者基本信息】 河北工业大学 ， 材料学， 2018， 硕士

【摘要】 6061铝合金由于其优异的加工性能、焊接性能以及良好的抗腐蚀性能被广泛应用于汽车制造业和航天航空领域的零部件。通常采用轧制变形和低温退火以提高其力学性能。然而,粗大的原始晶粒经常温轧制后会得到粗大的纤维组织导致其力学性能降低。因此,本课题制备出两种不同类型的非晶孕育剂来细化原始晶粒,并对非晶孕育剂特性和变质细化机理进行了研究。本文依据热力学规律设计并采用快速凝固处理的方法成功制备出ZrCuAl和较强非晶形成能力AlNiYCe非晶薄带孕育剂。分别将不同含量的非晶ZrCuAl和AlNiYCe薄带孕育剂加入6061铝合金中,当非晶ZrCuAl薄带孕育剂的添加量为0.3wt.%或非晶AlNiYCe薄带孕育剂的添加量0.4 wt.%时,其基体合金凝固组织晶粒细化效果最好。通过对比孕育和未孕育的6061铝合金可发现,在相同的轧制工艺下,轧制态和轧制退火态6061铝合金的晶粒均为纤维状,经非晶薄带ZrCuAl和AlNiYCe合金孕育的6061铝合金的拉长晶粒的宽度均比未孕育的6061铝合金的拉长晶粒较窄。孕育的轧制态和轧制退火态6061铝合金其力学性能包括维氏硬度、抗拉强度、屈服强度和延伸率都得到了显著的提升。当非晶ZrCuAl薄带孕育剂的含量为0.2 wt.%时,轧制退火态6061铝合金的维氏硬度、抗拉强度、屈服强度和延伸率分别达到了118.3?3.4 HV、358 MPa、346 MPa和8.9%。当非晶AlNiYCe薄带孕育剂的含量为0.4 wt.%时,轧制退火态6061铝合金的维氏硬度、抗拉强度、屈服强度和延伸率分别达到了123.8?1.5 HV、375 MPa、360 MPa和10.8%。本研究为室温轧制6061铝合金提供了一种性价比高和效率高的加工工艺。此外,本文阐明了非晶薄带ZrCuAl和AlNiYCe合金孕育6061铝合金的变质细化机理及强韧化机制。更多还原

【Abstract】 6xxx Al-Mg-Si aluminum alloy is widely used as structural components,such as automotive body sheets and aerospace applications,because of its excellent processability,weld ability and good corrosion resistance.The technique of room temperature rolling and following aging treatment is used to improve the mechanical properties of Al 6061 alloy.However,after room temperature rolling,initial coarse grains is replaced by coarse elongated grains resulting in the reduction of mechanical properties.Thus,in this academic dissertation,two different kinds of amorphous inoculants were prepared to refine and modify the initial coarse grain and the characterization of amorphous inoculant and the mechanism of refinement were also studied in detail.Amorphous ZrCuAl and AlNiYCe alloys were successfully prepared by vacuum rapid solidification technique according to the thermodynamic law.Different contents of amorphous ZrCuAl and AlNiYCe ribbons were added to aluminum 6061 alloy.The smallest grain of the inoculated aluminum 6061 alloy was got with addition of 0.3 wt.% ZrCuAl or 0.4 wt.%AlNiYCe amorphous ribbons,respectively.It can be seen that their initial grains have been replaced by elongated grains indicating the rolling has strong influence on the microstructure.The lamella spacing of inoculated RTR aluminum 6061 alloy decreases in the vertical direction and the remaining long fibrous grains are fragmented and reduced in thickness with addition of ZrCuAl or AlNiYCe amorphous alloy.The mechanical properties of inoculated RTR 6061 aluminum alloy before and after aging including vickers hardness,tensile strength,yield strength and elongation have been significantly improved.The vickers hardness,tensile strength,yield strength and elongation of RTR aluminum 6061 alloy inoculated by 0.2 wt.% amorphous ZrCuAl ribbons and after aging were 118.3?3.4 HV,358 MPa,346 MPa and 8.9%,respectively.The vickers hardness,tensile strength,yield strength and elongation of RTR aluminum 6061 alloy inoculated by 0.4 wt.% amorphous AlNiYCe ribbons and after aging were 123.8?1.5 HV,375 MPa,360 MP and10.8%,respectively.This study provides a cost-effective and high-efficiency processing technique of refinement for room temperature rolled Al 6061 alloy.Moreover,the refinement and reinforcement mechanism of the 6061 aluminum alloy were studied in detail.更多还原