Ti基块体非晶及含Ti高熵块体非晶合金制备与性能研究

发布时间：2018-06-14 16:38

  本文选题：Ti基非晶合金 + 高熵块体非晶合金　； 参考：《清华大学》2015年博士论文

【摘要】：Ti基块体非晶合金因具有低比重高强度高弹性变形量和好的耐蚀性等优异性能,是具有较好应用前景的轻质高强材料,受到了研究人员的高度关注。但Ti基合金的非晶形成能力有限,这将会限制其应用范围。因此,研究影响Ti基合金非晶形成能力的主要因素,研发具有较强非晶形成能力的Ti基合金系有着重要意义。研究发现采用Ag、Cu和Ni等元素合金化的方法,可显著提高了Ti-Zr-Be非晶合金系的非晶形成能力、热稳定性和综合力学性能。研发的四元Ti41Zr25Be34-x Agx、Ti4 1Zr25Be34-x Cux、Ti45Zr20Be35-x Cux、Ti41Zr25Be34-x Nix和Ti45Zr20Be35-x Nix合金系均具有较大非晶形成能力,其中部分Ti-Zr-Be-Ni合金形成非晶的临界尺寸达Φ20 mm,是迄今报道的非晶形成能力最强的四元Ti基非晶合金。另外,还研发出临界尺寸为Φ10 mm的高Ti含量Ti50Zr16Be24Ni10块体非晶合金,这是临界尺寸达到厘米级非晶合金中Ti含量最高的合金,其比强度为3.86×105 N·m/kg,塑性应变量为5.7±0.1%。通过分析等效原子尺寸差异δ、等效电负性差异Δx和混合焓ΔHmix对Ti基合金非晶形成能力的影响规律,在总结归纳已有结果的基础上,发现形成非晶的临界尺寸达到厘米级以上的Ti基非晶合金同时具有较大的等效原子尺寸差异(0.1176≤δ≤0.1333)、较大的电负性差异(0.1194≤Δx≤0.1837),同时还有较大的混合焓负值(-23.81 k J/mol≤ΔHmix≤-33.15 k J/mol)。上述结果可为新型Ti基块体非晶合金的成分设计提供指导。发现含钛伪五元Ti_(20)Zr_(20)Hf_(20)Be_(20)(Cu20-x Nix)高熵合金系具有强的非晶形成能力,形成非晶的临界尺寸均大于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高熵非晶合金的临界尺寸分别达Φ30 mm和Φ15 mm,是迄今临界尺寸最大的高熵块体非晶合金和五元高熵块体非晶合金;研发的高熵块体非晶合金具有较高的屈服强度及较大的压缩塑性应变;同时,Ni含量较高时,其抗晶化能力较强;Ti_(20)Zr_(20)Hf_(20)Be_(20)(Cu7.5Ni12.5)高熵合金具有较大的混合熵以及体系中最低的固液相吉布斯自由能差值,使其具有体系中最强的非晶形成能力。
[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 卤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，

本文编号：2018186