本文選題：Zr-Al-V三元系 + 相圖　； 參考：《湘潭大學(xué)》2017年碩士論文

【摘要】：開發(fā)耐熱鋁材料是鋁合金研究的一個重要方向,而其中鈧(Sc)元素作為鋁合金添加劑最為有效,僅微量添加,即可使鋁合金有極高的強(qiáng)化效應(yīng)、抗腐蝕性能、優(yōu)異的焊接性能和耐熱性能。但鈧的價格昂貴,導(dǎo)致鈧鋁合金應(yīng)用范圍極小,限于體育和軍事。由于鋯(Zr)在鋁合金中能夠形成適合的強(qiáng)化相,工作溫度下在Al基體中的固溶度小,在Al中的擴(kuò)散系數(shù)小,也不影響合金的可鑄造性,因此極有希望替代鈧成為鋁合金中的添加劑。此外,釩在鋁合金中相比于其它常見添加元素,其擴(kuò)散率最小,在鋁合金中形成VAl11等難溶化合物,在熔鑄過程中起細(xì)化晶粒作用。并且也有細(xì)化再結(jié)晶組織、提高再結(jié)晶溫度的作用。為進(jìn)一步了解合金元素之間的作用機(jī)理及相關(guān)系,相圖的研究顯得極為重要。本工作主要采用平衡合金法,結(jié)合掃描電鏡—能譜儀(SEM-EDS)和X-射線衍射儀(XRD)等對樣品進(jìn)行檢測分析,并測定了Zr-Al-V三元系化合物在800℃等溫截面下的相關(guān)系。在該體系中,發(fā)現(xiàn)一個新的三元化合物,命名為T相。經(jīng)實(shí)驗(yàn)發(fā)現(xiàn),Zr-Al-V體系在800℃等溫截面共有15個三相區(qū),分別為Al+Al3V+Al3Zr、Al8V5+Al3V+Al3Zr、Al8V5+T+Al3Zr、Al3Zr+T+Al2Zr、Al2Zr+T+V、Al2Zr+Al3Zr2+Al3Zr4、Al2Zr+Al3Zr4+Al2Zr3、Al2Zr+Al2Zr3+AlZr2、Al2Zr+AlZr2+AlZr3、Al2Zr+AlZr3+β-Zr、Al2Zr+V2Zr+β-Zr、Al2Zr+V2Zr+V、Al3Zr2+AlZr+Al3Zr、α-Zr+β-Zr+AlZr3和T+Al8V5+V。其中Al3Zr2+AlZr+Al3Zr、α-Zr+β-Zr+AlZr3和T+Al8V5+V三個三相區(qū)是從已有的實(shí)驗(yàn)數(shù)據(jù)中推導(dǎo)出來的。實(shí)驗(yàn)結(jié)果表明,在800℃下,T可與V,Al2Zr,Al3Zr,Al8V5平衡共存,它的成分范圍是10.0~16.5 at.%Zr,52.8~55.2 at.%Al和29.3~36.3 at.%V。并且V在Al2Zr中的最大溶解度達(dá)54.1at.%。
[Abstract]:The development of heat-resistant aluminum material is an important research direction of aluminum alloy, among which scandium scum is the most effective additive for aluminum alloy. Only a small amount of addition can make aluminum alloy have extremely high strengthening effect and corrosion resistance. Excellent weldability and heat resistance. However, the price of scandium is very high, which leads to a very small range of applications, limited to sports and military. Because zirconium) can form a suitable strengthening phase in aluminum alloy, the solution in Al matrix is small at operating temperature, the diffusion coefficient in Al is small, and the castability of the alloy is not affected. Therefore, it is very promising to replace scandium as an additive in aluminum alloy. In addition, vanadium has the smallest diffusivity compared with other common elements in aluminum alloy, and forms insoluble compounds such as VAl11 in aluminum alloy, which plays a role in grain refinement in the process of melting and casting. It also has the function of refining recrystallization structure and increasing recrystallization temperature. In order to further understand the interaction mechanism and phase relationship between alloying elements, the study of phase diagram is very important. In this work, the equilibrium alloy method was used to determine the phase relationship of Zr-Al-V ternary compounds under isothermal section at 800 鈩，

本文編號：1975135