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研究了脉冲电流对2091铝锂合金在高应变速率下超塑变形的力学行为及断裂机制的影响.结果表明,施加脉冲电流可使2091铝锂合金在高应变速率区间(10~(-2)S~(-1))仍有高应力应变速度敏感指数和超塑性性能.扫描电镜观察表明,施加脉冲电流后,2091铝锤合金在高应变速率区间的超塑变形断裂由通常的晶界撕裂机制转变成典型的超塑性断裂(粒子及晶界处形成孔洞并相互连接以致断裂).对断口的观察表明,施加脉冲电流的试样表现为典型的超塑性沿晶断裂,未加电流的试样是带有浅韧窝的沿晶断裂.研究表明脉冲电流促进高温下的原子扩散是产生这些结果的直接原因.
The effect of pulse current on the mechanical behavior and fracture mechanism of 2091 Al-Li alloy under high strain rate was investigated. The results show that 2091 Al-Li alloy can be sintered at high strain rate (10 ~ (-2) S -1 still shows high stress-strain sensitivity index and superplasticity.The SEM observations show that the superplastic deformation fracture of 2091 aluminum alloy in the high strain rate range is caused by the usual grain boundary tearing Cracking mechanism into a typical superplastic fracture (particles and grain boundaries formed and connected to each other so that the fracture.) The observation of the fracture shows that the impulse current of the sample showed a typical superplasticity along the intergranular fracture, no current The samples were intergranular fractures with shallow dimples.Research shows that pulsed current promotes atom diffusion under high temperature is the direct reason for these results.