【作者】 王宁；

【导师】 管仁国；

【作者基本信息】 东北大学 ， 材料工程（专业学位）， 2019， 硕士

【摘要】 Cu-Zr合金作为铜合金中典型的时效型强化合金,具有较高强度、良好的导电导热性能,在集成电路中的引线框架、高铁接触导线、电机制造等领域都有广泛的应用。其优良的性能和广阔的应用前景,引起了越来越多的学者的重视,逐渐成为近年来铜合金的重要研究内容之一。Cu-Zr合金中添加适量的稀土元素能够净化熔体,有效地提高Cu-Zr合金的综合性能,因此Cu-Zr-RE合金的研究是十分必要。目前国内关于Cu-Zr-RE合金的研究主要集中在混合稀土对Cu-Zr合金的组织性能的影响上,关于稀土元素对形变热处理过程中合金组织和性能的影响的分析不够深入。有关含单一稀土元素Y的Cu-Zr-Y合金组织和性能影响的研究十分有限,关于Cu-Zr-Y系合金在热处理和变形过程的组织演化和性能变化规律的研究更是鲜有报道。故本文选择Y元素为添加元素,设计并通过真空熔炼法制备了 Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2),对合金进行热处理及轧制变形处理,旨在通过研究Y、Zr元素在铜合金中的相存在形式及其在热处理和轧制变形过程中与基体之间的相互作用规律,以及热处理参数,轧制变形参数等对合金的组织性能的影响,进而制备出高性能Cu-Y-Zr合金。采用扫描电子显微镜(SEM),能量色散光谱(EDS),X射线衍射(XRD),透射电子显微镜(TEM)等检测手段,观察铸态、热处理及变形后的Cu-0.5Y-xZr合金的组织,并采用显微维氏硬度计和万能试验机测试了合金的力学性能。得到主要研究结果如下:(1)观察时效后Cu-0.5Y-xZr(wt.%)的宏观相组成及形貌特征,发现时效后Cu-0.5Y-xZr(wt.%)合金中析出相主要以三种不同形貌的方式存在:沿晶界析出的大尺寸长条状析出相,独立存在于晶粒内部尺寸约为30 μm以下的棒状及块状析出相。且当Zr含量较低时(x=0.05/0.1),合金中的析出相以长条状为主,当Zr含量较高时(x=0.15/0.2),合金中块状与棒状形貌的析出相增多。(2)Cu-0.5Y-0.05Zr(wt.%)合金经460℃时效3 h后获得最大硬度值,最大硬度值为为 84.89 HV;Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)合金在 460℃ 时效 2 h后均达到最大硬度值,最大硬度值分别为87.35 HV、92.24 HV和95.16 HV。Cu-0.5Y-xZr(wt.%)合金经460℃时效3 h,导电率得到较大提升,而后随着时效时间的延长导电率趋于稳定。(3)随着轧制压下量的增加,Cu-0.5Y-xZr(wt.%)合金的强度硬度逐渐增大;相比较于未变形Cu-0.5Y-xZr(wt.%)合金,轧制后合金的断后延伸率明显下降,随着压下量的增加,断后延伸率的降低幅度逐渐减小。此外,Cu-0.5Y-xZr(wt.%)导电率随压下量的增加而下降,但轧制变形对Cu-0.5Y-xZr(wt.%)的导电率影响并不大。更多还原

【Abstract】 Cu-Zr alloy is a typical kind of aging strengthened alloy.It has excellent mechanical performance as well as extremely high thermal and electrical conductivity.It has already been widely used in the integrated circuit,contact wires of high speed rail,electromotor and other fileds.Its excellent performance and bright prospect have attracted more and more researchers’ attention,and it has gradually become one of the important research contents of copper alloys in recent years.The addition of a proper amount of rare earth elements in Cu-Zr alloy can purify the melt and improve the mechanical properties of Cu-Zr alloy effectively.Therefore,the study of Cu-Zr-RE alloy is pretty necessary.At present,the domestic researches on Cu-Zr-RE alloy mainly focus on the influence of mixed rare earth elements on the micro structure and properties of Cu-Zr alloy.The analysis of the influence of RE elements on the microstructure and properties of Cu-Zr alloy during deformation and heat treatment has not been deeply conducted yet.The researches on the influence of single rare earth element Y on the microstructure and properties of Cu-Zr alloy are limited.The evolution regulations of microstructure and properties of Cu-Zr-Y alloy during heat treatment and deformation are rarely studied.In this paper,Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys were designed and vacuum-melted.The heat treatment and rolling deformation were then carried on the as-cast alloys.The research aims were to prepare excellent performance Cu-0.5Y-xZr alloys by studying the existence forms of Y and Zr elements in copper alloy and the rules of interaction between the matrix and second phases during heat treatment and rolling deformation as well as the influence of heat treatment parameters and rolling deformation parameters on the microstructure and properties of the alloys.The microstructures of the as-cast,heat-treated and rolled Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys were observed by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and transmission electron microscopy(TEM).The mechanical properties of the alloys were tested using a microhardness tester and a universal testing machine.The main findings are as follows:(1)Precipitated phases with three different morphologies were found by observing the SEM images of aged Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0,15/0.2)alloys.They are large-sized elongated precipitate phase precipitated along the grain boundary,rod-shaped and block-like precipitate phases with the sizes bellow 30μm in the grain.In addition,with the increase of Zr contents,the quantities of rod-shaped and block-like precipitate phases increase,while that of the elongated precipitate phases decrease.(2)Cu-0.5Y-0.05Zr(wt.%)alloy obtained the maximum hardness after aging at 460℃ for 3 h with the value of 84.89 HV.Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys gained the maximum hardness after aging at 460℃ for 2 h,and the maximum hardness were 87.35 HV,92.24 HV and 95.16 HV,respectively.The electrical conductivities of Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys could be greatly improved after aging at 460℃ for 3 h.And then the electrical conductivities tended to be stable with the prolongation of aging time.(3)As the rolling reduction increased,the strength and hardness of the Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys were gradually improved.The elongations of the Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys decreased significantly compared to as-cast alloys.However,the elongations were slowly increased with the increasing of the reduction.In addition,the conductivities of Cu-0.5Y-xZr(wt.%,x=0.05/0.1/0.15/0.2)alloys decreased with increasing of reduction.更多还原