氧含量及过热度对铸态Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_5大体积玻璃合金微观组织结构及力学性能的影响

Effect of Oxygen Impurity and Overheating on Microstructure and Mechanical Properties of As-cast Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_5 Bulky Glass Alloys

摘要:

利用射流成型法制备了厚度为２ｍｍ的Ｚｒ５２．５Ｃｕ１７．９Ｎｉ１４．６Ａｌ１０Ｔｉ５金属玻璃薄板，通过控制氧含量和过热度来改变 玻璃薄板中淬态结晶相的体积分数。研究表明：低的氧含量水平和高的过热度有利于提高该合金的玻璃形成能力，形 成完全非晶的合金；完全非晶的 ２ｍｍＺｒ５２．５Ｃｕ１７．９Ｎｉ１４．６Ａｌ１０Ｔｉ５大体积金属玻璃薄板其断裂应力为 １７１０ＭＰＳ，弹性模量为 ８０ＧＰａ，弹塑性为２．２％。提高合金中的氧含量水平或者降低熔体过热度都有利于结晶相析出。基体中出现２％和６％的结晶相时，断裂应力分别降为１５８ＭＰａ和１２２０ＭＰａ．淬态结晶相的析出改变了Ｚｒ５２．５Ｃｕ１７．９Ｎｉ１４．６Ａｌ１０Ｔｉ５大体积金属玻 璃剪切流变的变形方式，使材料脆断。

Abstract:

Zr52. 5Cu17. 9Ni14.6Al1.0Ti5 bulky glass sheets with thickness of 2mm were prepared by a water-cooled copper mold casting. The volume fraction of quenched-in crystallines were controlled by changing oxygen impurity content and overheating level. The results show: low oxygen content and enough large overheating level can improve the glass formation ability of the present ahoy. Fully amorphous sheet with a thickness of 2mm displays high fractured strength (1 710MPa). Samples with volume fraction of 2% still have high fractured strength (1 580MPa), but that of samples with volume fraction of 7% reduce rapidly to 1 220MPa. The reason for decreasing of fracture strength is that quenched-in crystals embedded on the amorphous matrix induce initiation and propagation of crack.