本文選題：Ti基非晶合金 + 高熵塊體非晶合金��； 參考：《清華大學》2015年博士論文

【摘要】：Ti基塊體非晶合金因具有低比重高強度高彈性變形量和好的耐蝕性等優(yōu)異性能,是具有較好應(yīng)用前景的輕質(zhì)高強材料,受到了研究人員的高度關(guān)注。但Ti基合金的非晶形成能力有限,這將會限制其應(yīng)用范圍。因此,研究影響Ti基合金非晶形成能力的主要因素,研發(fā)具有較強非晶形成能力的Ti基合金系有著重要意義。研究發(fā)現(xiàn)采用Ag、Cu和Ni等元素合金化的方法,可顯著提高了Ti-Zr-Be非晶合金系的非晶形成能力、熱穩(wěn)定性和綜合力學性能。研發(fā)的四元Ti41Zr25Be34-x Agx、Ti4 1Zr25Be34-x Cux、Ti45Zr20Be35-x Cux、Ti41Zr25Be34-x Nix和Ti45Zr20Be35-x Nix合金系均具有較大非晶形成能力,其中部分Ti-Zr-Be-Ni合金形成非晶的臨界尺寸達Φ20 mm,是迄今報道的非晶形成能力最強的四元Ti基非晶合金。另外,還研發(fā)出臨界尺寸為Φ10 mm的高Ti含量Ti50Zr16Be24Ni10塊體非晶合金,這是臨界尺寸達到厘米級非晶合金中Ti含量最高的合金,其比強度為3.86×105 N·m/kg,塑性應(yīng)變量為5.7±0.1%。通過分析等效原子尺寸差異δ、等效電負性差異Δx和混合焓ΔHmix對Ti基合金非晶形成能力的影響規(guī)律,在總結(jié)歸納已有結(jié)果的基礎(chǔ)上,發(fā)現(xiàn)形成非晶的臨界尺寸達到厘米級以上的Ti基非晶合金同時具有較大的等效原子尺寸差異(0.1176≤δ≤0.1333)、較大的電負性差異(0.1194≤Δx≤0.1837),同時還有較大的混合焓負值(-23.81 k J/mol≤ΔHmix≤-33.15 k J/mol)。上述結(jié)果可為新型Ti基塊體非晶合金的成分設(shè)計提供指導。發(fā)現(xiàn)含鈦偽五元Ti_(20)Zr_(20)Hf_(20)Be_(20)(Cu20-x Nix)高熵合金系具有強的非晶形成能力,形成非晶的臨界尺寸均大于Φ12 mm。其中,Ti_(20)Zr_(20)Hf_(20)Be_(20)(Cu7.5Ni12.5)和Ti_(20)Zr_(20)Hf_(20)Be_(20)Ni20高熵非晶合金的臨界尺寸分別達Φ30 mm和Φ15 mm,是迄今臨界尺寸最大的高熵塊體非晶合金和五元高熵塊體非晶合金;研發(fā)的高熵塊體非晶合金具有較高的屈服強度及較大的壓縮塑性應(yīng)變;同時,Ni含量較高時,其抗晶化能力較強;Ti_(20)Zr_(20)Hf_(20)Be_(20)(Cu7.5Ni12.5)高熵合金具有較大的混合熵以及體系中最低的固液相吉布斯自由能差值,使其具有體系中最強的非晶形成能力。
[Abstract]:Ti-base bulk amorphous alloys have attracted much attention due to their excellent properties such as low specific gravity, high strength, high elastic deformation and good corrosion resistance. However, the amorphous forming ability of Ti-based alloy is limited, which will limit its application range. Therefore, it is of great significance to study the main factors affecting the amorphous forming ability of Ti-base alloy and to develop the Ti-base alloy system with strong amorphous forming ability. It is found that the amorphous forming ability, thermal stability and comprehensive mechanical properties of Ti-Zr-Be amorphous alloy system can be significantly improved by means of alloying elements such as Agnu Cu and Ni. The quaternary Ti41Zr25Be34-x Agxnx Ti41Zr25Be34-x Cuxfen Ti45Zr20Be35-x Cuxfen Ti41Zr25Be34-x Nix and Ti45Zr20Be35-x Nix alloys have higher amorphous forming capacity, and some Ti-Zr-Be-Ni alloys have the critical size of 桅 20mm for amorphous formation. In addition, a high Ti content Ti50Zr16Be24Ni10 bulk amorphous alloy with critical size of 桅 10mm has been developed. This alloy has the highest Ti content in the critical size of centimeter amorphous alloy. Its specific strength is 3.86 脳 10 ~ 5 N / m ~ (-1) kg, and the plastic strain is 5.7 鹵0.1. By analyzing the influence of equivalent atom size difference 未, equivalent electronegativity difference 螖 x and mixing enthalpy 螖 H mix on the amorphous formation ability of Ti-base alloy, the existing results are summarized. It is found that Ti-base amorphous alloys with critical size above centimeter level have larger difference in equivalent atomic size (0.1176 鈮，

本文編號：2018186