【摘要】：超高強7×××(Al-Zn-Mg-Cu)系鋁合金是一種具有很高的比強度和硬度、良好的熱加工性和焊接性能、較好的耐蝕性和較高的韌性的結(jié)構(gòu)材料,被廣泛應(yīng)用于航空航天、汽車、機(jī)械制造等領(lǐng)域。Al-Zn-Mg-Cu系合金的性能受合金成分、熱處理工藝及制備方法的影響很大,特別是Zr、Sc等微量合金元素對合金組織和性能的影響尤為顯著。因此為了研究新的超高強鋁合金,了解合金元素之間的作用機(jī)理及相關(guān)系顯得極其重要。本文主要從Zn-Al-Zr三元系的相關(guān)系出發(fā)進(jìn)行研究,為研發(fā)出性能更加優(yōu)異的鋁合金材料提供理論依據(jù)。在本研究工作中,主要采用平衡合金實驗法及擴(kuò)散偶微區(qū)分析法,并結(jié)合掃描電子顯微鏡和能譜儀(SEM-EDS)、X-射線衍射儀(XRD)和電子探針儀(EPMA)等對樣品進(jìn)行檢測分析,測定了Zn-Al-Zr三元系450℃等溫截面和800℃等溫截面的相關(guān)系。在改體系中發(fā)現(xiàn)一個新的三元化合物,命名為T相。經(jīng)分析發(fā)現(xiàn)它屬于立方晶系、簡單立方結(jié)構(gòu),其點陣參數(shù)a=0.5756 nm。Zn-Al-Zr三元系在450℃等溫截面中共存在16個三相平衡區(qū),實驗測定了15個,分別為: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。根據(jù)相區(qū)接觸法則推測出了第16個三相平衡區(qū)Zr3Al2+T+Zn3Zr。該溫度下T與L-Zn,α-Al,ZrAl3,ZrAl2,Zr2Al3,Zr Al,Zr4Al3,Zr3Al2,Zn14Zr,Zn6Zr和Zn3Zr等能夠平衡共存,它的成分范圍是26at.%~27 at.%Zr,11.9 at.%~58.5 at.%Zn。實驗測定了Zn-Al-Zr三元系800℃等溫截面,在該截面中發(fā)現(xiàn)了9個三相平衡區(qū):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。該溫度下T仍然存在,且T與L,ZrAl3,ZrAl2,Zr2Al3,ZrAl,Zr4Al3,Zr2Al,Zr3Al2,Zn3Zr和ZnZr等能夠平衡共存,它的成分范圍是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，

本文編號：2228552