Zn-Al-Zr三元系相平衡的研究

发布时间：2018-09-07 14:38

【摘要】：超高强7×××(Al-Zn-Mg-Cu)系铝合金是一种具有很高的比强度和硬度、良好的热加工性和焊接性能、较好的耐蚀性和较高的韧性的结构材料,被广泛应用于航空航天、汽车、机械制造等领域。Al-Zn-Mg-Cu系合金的性能受合金成分、热处理工艺及制备方法的影响很大,特别是Zr、Sc等微量合金元素对合金组织和性能的影响尤为显著。因此为了研究新的超高强铝合金,了解合金元素之间的作用机理及相关系显得极其重要。本文主要从Zn-Al-Zr三元系的相关系出发进行研究,为研发出性能更加优异的铝合金材料提供理论依据。在本研究工作中,主要采用平衡合金实验法及扩散偶微区分析法,并结合扫描电子显微镜和能谱仪(SEM-EDS)、X-射线衍射仪(XRD)和电子探针仪(EPMA)等对样品进行检测分析,测定了Zn-Al-Zr三元系450℃等温截面和800℃等温截面的相关系。在改体系中发现一个新的三元化合物,命名为T相。经分析发现它属于立方晶系、简单立方结构,其点阵参数a=0.5756 nm。Zn-Al-Zr三元系在450℃等温截面中共存在16个三相平衡区,实验测定了15个,分别为:Zn14Zr+T+L-Zn、Zn14Zr+T+Zn6Zr、Zn6Zr+T+Zn3Zr、α-Al+T+L-Zn、α-Al+T+Zr Al3、ZnZr+Zn2Zr+Zn3Zr、α-Zr+ZnZr+Zr3Al、Zn Zr+Zr3Al+Zn3Zr、Zr3Al+Zr2Al+Zn3Zr、Zr2Al+Zr3Al2+Zn3Zr、Zr3Al2+Zr4Al3+T、Zr4Al3+ZrAl+T、ZrAl+Zr2Al3+T、Zr2Al3+ZrAl2+T和Zr Al2+T+Zr Al3。根据相区接触法则推测出了第16个三相平衡区Zr3Al2+T+Zn3Zr。该温度下T与L-Zn,α-Al,ZrAl3,ZrAl2,Zr2Al3,Zr Al,Zr4Al3,Zr3Al2,Zn14Zr,Zn6Zr和Zn3Zr等能够平衡共存,它的成分范围是26at.%~27 at.%Zr,11.9 at.%~58.5 at.%Zn。实验测定了Zn-Al-Zr三元系800℃等温截面,在该截面中发现了9个三相平衡区:ZrAl3+T+L;Zn2Zr+Zn3Zr+T、Zn3Zr+T+L、Zr2Al+Zr3Al2+T、Zr3Al2+Zr4Al3+T、Zr2Al3+ZrAl2+T、ZrAl2+T+ZrAl3、Zr2Al3+ZrAl+T和ZrAl+Zr3Al2+T。该温度下T仍然存在,且T与L,ZrAl3,ZrAl2,Zr2Al3,ZrAl,Zr4Al3,Zr2Al,Zr3Al2,Zn3Zr和ZnZr等能够平衡共存,它的成分范围是26.4 at.%~28.55 at.%Zr,17.2 at.%~55.1 at.%Zn。
[Abstract]:Super high strength 7 脳 脳 脳 (Al-Zn-Mg-Cu) aluminum alloy is a kind of structural material with high specific strength and hardness, good hot working property and weldability, good corrosion resistance and high toughness. It is widely used in aerospace and automobile. The properties of Al-Zn-Mg-Cu alloy are greatly affected by the composition of alloy, heat treatment process and preparation method, especially the effect of trace elements such as Zr,Sc on the microstructure and properties of the alloy. Therefore, it is very important to understand the interaction mechanism and phase relationship between alloy elements in order to study new super-high-strength aluminum alloys. In this paper, the phase relationship of Zn-Al-Zr ternary system is studied, which provides a theoretical basis for the development of aluminum alloy with better properties. In this work, the equilibrium alloy experiment method and diffusion couple microanalysis method were used to detect and analyze the samples with scanning electron microscope (SEM) and energy dispersive spectrometer (SEM-EDS) X-ray diffractometer (XRD) and electron probe (EPMA). The phase relationships of 450 鈩，

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