Zr基非晶合金在过冷液相区静液挤压的变形行为及结构

研究了Zr41.2Ti13.8Cu12.5Ni10Be22.5非晶合金在过冷液相区内静液挤压的变形行为以及结构变化。结果表明:非晶合金在高应变速率下产生了明显的塑性变形,直径从16 mm变为12 mm,断裂为4段,且样品断口上随机分布着充分发展与未充分发展的脉纹式切变带,由此可看出非晶合金的变形为非牛顿体变形行为;挤压后的样品约有3%的非晶相发生晶化,在非晶基体上析出10~20 nm的纳米晶粒,导致挤压后非晶合金的热稳定性降低;静液挤压高应变速率变形条件使非晶合金产生非均匀流变,是造成非晶合金断裂的主要原因。

Deformation behavior and structure of Zr base bulk amorphous alloy in supercooled liquid region by hydrostatic extrusion

The deformation behavior and structure of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk amorphous alloy processed at 663 K with strain rate of 0.28 s^-1 by hydrostatic extrusion were studied. The results show that the alloy undergoes obvious plastic elongation, the specimen fractures into four sections and the diameter changes from 16 mm to 12 mm. The fracture surfaces distribute randomly well developed and partially developed veinal patterns. The deformation behavior of alloy is non-Newtonian flow behavior. About 3% amorphous matrix of extruded specimen transforms crystal, the crystal particles with size of 10 -20 mm are precipitated in the amorphous matrix, the thermostability of the extruded specimen was lowered. The failure of the alloy is mainly attributed to non-uniform viscous flow under high strain rate resulting from the hydrostatic extrusion process.