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研究Zr52.5Cu17.9Ni14.6Al10Ti5块体非晶合金由于铸造过程中表面与心部冷却速率差异诱发的表面软化层对其室温压缩行为的影响。通过逐层除去铸造表面软化层,块体非晶试样表现出脆性-韧性转变。在室温压缩时,除去表面软化层的试样呈现大量致密、均匀分布的剪切带和较好的塑性;而未除去表面软化层的试样仅萌生出少量剪切带,且发生灾难性断裂。除去软化层的试样变形后自由体积增加,说明在压缩过程中发生了应变软化。除去软化层的试样组织结构相对均匀,剪切带稳定扩展,断面平滑;而未除去表面软化层的试样则呈现出多样的断面形貌。
The effect of surface softening layer induced by the difference of surface and core cooling rate on the compression at room temperature of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloy was studied. The bulk amorphous samples show a brittle-ductile transition by removing the cast surface softening layer by layer. When compressed at room temperature, the samples with the surface softening layer removed exhibited a large number of dense and uniformly distributed shear bands and good ductility. However, the specimens without the surface softening layer initiated only a small amount of shear bands and suffered catastrophic failure . After removing the softened layer, the free volume increases after deformation, indicating that strain softening occurred during the compression. The samples with the softening layer removed are relatively uniform in structure, the shear band is expanded steadily, and the section is smooth. However, the samples with no surface softening layer show a variety of cross-sectional morphology.