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通过化学气相沉积方法合成截面为六边形的单晶钨纳米晶须,利用纳米压痕仪和原子力显微镜对硅基底上的钨纳米晶须的力学性能进行表征。纳米压痕测试结果表明,钨纳米晶须的硬度为(6.2±1.7)GPa,弹性模量为(225±20)GPa。对比研究结果表明,钨纳米晶须的硬度与钨微米晶须的硬度相当,但比块体钨单晶高35%。这种硬度的增高是由于具有完好晶体结构的钨晶须在压痕测试中不会出现块体钨单晶中的位错崩。钨纳米晶须的弹性模量相当于钨微米晶须的80%,主要是由于纳米晶须的尺寸效应和测量过程中的基底效应所致。
The hexagonal single crystal tungsten nanowhiskers were synthesized by chemical vapor deposition. The mechanical properties of tungsten nanowhiskers on silicon substrate were characterized by nanoindentation and atomic force microscopy. The results of nanoindentation test showed that the hardness of tungsten nanowhiskers was (6.2 ± 1.7) GPa and the elastic modulus was (225 ± 20) GPa. The results of the comparative study show that the hardness of tungsten nanowhiskers is comparable to that of tungsten micron whiskers, but it is 35% higher than that of bulk tungsten single crystals. This increase in hardness is due to the fact that tungsten whiskers with intact crystal structure do not suffer from dislocations in bulk tungsten single crystals in the indentation test. The elastic modulus of tungsten nanowhiskers is equivalent to 80% of tungsten micron whiskers, mainly due to the size effect of nanowhiskers and the substrate effect during the measurement.