(湘潭大學(xué) 土木工程與力學(xué)學(xué)院，湘潭 411105)
摘 要: 通過原子力顯微鏡(AFM)納米壓痕實驗研究傳統(tǒng)納米壓痕實驗形成的Fe基非晶合金剪切帶區(qū)域及未變形區(qū)域的變形；結(jié)合壓痕形貌實時原位觀測，探討塊體非晶合金塑性變形局域化的原因。結(jié)果表明：最大載荷44.6 μN下，材料的剪切帶、剪切帶間和未變形區(qū)域的AFM納米壓痕殘余面積分別為3 274.7、2 976.5和2 879.2 nm2，對應(yīng)的硬度分別為13.62、14.98和15.49 GPa，剪切帶區(qū)域的硬度值比未變形區(qū)域的硬度值降低了約10%，說明塑性變形過程中，過剩自由體積的產(chǎn)生使剪切帶結(jié)構(gòu)發(fā)生軟化。
關(guān)鍵字: 塊體非晶合金；剪切帶；原子力納米壓痕；硬度
shear bands of bulk metallic glasses
（College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China）
Abstract:The deformation behaviors of the shear bands produced by traditional indentation test and undeformed region of a Fe-based bulk metallic glass (BMG) were investigated by atomic force microscope (AFM) nanoindentation tests. Combining with in-situ observation of the indentation morphology, the origin of the localization of plastic deformation of BMG was studied. The results show that, under the maximum load of 44.6 μN, the residual impressions areas caused by AFM indenter in the shear band, inter-band and undeformed regions are 3 274.7, 2 976.5 and 2 879.2 nm2 with the corresponding hardness of 13.62, 14.98 and 15.49 GPa, respectively. The hardness of shear band is about 10% smaller than that of undeformed region, which indicates that the plasticity in metallic glasses is associated with strain softening induced by the creation of excess free volume during deformation.
Key words: bulk metallic glass; shear band; atomic force microscope nanoindentation; hardness
