离子辐照对Zr_(50.7)Cu_(28)Ni_9Al_(12.3)非晶合金力学性能的影响

Effects of Ion Irradiation on Mechanical Property of Zr_(50.7)Cu_(28)Ni_9Al_(12.3) Amorphous Alloy

非晶合金有潜力成为新一代核材料,离子辐照对其力学性能的影响决定了其使用价值。在不同剂量的Au离子辐照下,探讨了Zr_(50.7)Cu_(28)Ni_9Al_(12.3)非晶合金力学性能的变化过程。原子力显微镜以及正电子湮没寿命谱分析表明,在离子辐照后,非晶合金的自由体积尺寸增大、密度下降,总自由体积增加。透射电子显微镜分析表明,辐照剂量在达到50 dpa时非晶合金开始有纳米晶析出,随着辐照剂量的增加,纳米晶尺寸在增加、密度变大。纳米压痕试验表明,离子辐照后非晶合金的硬度减小,在高剂量时硬度又有增加的趋势。离子辐照下非晶合金的硬度变化是自由体积以及纳米晶竞争的结果。自由体积使非晶合金软化,纳米晶析出使非晶合金硬化。

Amorphous alloy is a type of promising nuclear material. The effects of ion irradiation on the mechanical property of amorphous alloy determine its application value. The mechanical properties of Zr50.7Cu28Ni9Al12.3 amorphous alloy was investigated with different doses of Au ions irradiation. Atomic force microscopy and positron annihilation lifetime spectroscopy experiments show that ion irradiation can enlarge the free volume and decrease the density. Transmission electron microscope analysis show that the nanocrystallines begin to segregate in amorphous alloy at 50 dpa, and the size and density of nanocrystallines increase with increasing irradiation dose. Nanoindentation testing show the hardness of the amorphous alloy decreases at a low irradiation dose while increases at a high irradiation dose. The variation of hardness of amorphous alloy can be ascribed to a consequence of the competition mechanism between free volume and nanocrystallines. Free volume can soften the amorphous alloy, while segregated nanocrystallines can harden the amorphous alloy.