摘要
研究等温退火和预压处理对Cu_(36)Zr_(48)Al_8Ag_8大块非晶合金力学性能的共同影响。首先,将铸态样品在743 K退火10 min,然后对退火后的样品进行预压处理,在800 MPa压力下分别预压1、3、5和10 h。结果表明,退火处理后在非晶基体中形成了尺寸为10 nm左右的纳米晶并极大地湮灭了自由体积,从而导致大块非晶合金完全丧失塑性。在800 MPa下预压处理合适的时间(5 h)可以部分地恢复自由体积,进而部分地恢复大块非晶合金的塑性。而过长的预压时间(10 h)将导致自由体积的再次减小,主要源于纳米晶的过分长大。
The combined effects of isothermal annealing and pre-compression on the mechanical properties of Cu36Zr48Al8Ag8 bulk metallic glass (BMG) were investigated. The as-cast specimens were first annealed at 743 K for 10 min, and then pre-compressed under 800 MPa for 1, 3, 5 and 10 h, respectively. The results indicated that annealing resulted in the formation of nanocrystals with a diameter of -10 nm in the amorphous matrix and a drastic decrease of the free volume, leading to complete loss of the plasticity of the BMG. Applying pre-compression under a stress of 800 MPa for a proper duration (5 h) resumed part of the lost free volume in the BMG matrix and therefore partially recovered the plasticity. A very long period of pre-compression (10 h) decreased the free volume again, which was caused by the excessive crystal growth.
基金
Projects(51328101,51301142)supported by the National Natural Science Foundation of China
Project(2015JJ2206)supported by Hunan Provincial Natural Science Foundation of China
关键词
大块非晶合金
退火
预压
自由体积
纳米晶
bulk metallic glasses
annealing
pre-compression
free volume
nanocrystal