Cu-12%Nb复合线材退火过程中微观组织及力学性能研究

Study on the microstructure and mechanical properties of Cu-12%Nb composite wires during annealing

摘要:

采用扫描电镜(SEM)、透射电镜(TEM)和X射线衍射(XRD)表征了变形态及不同温度退火的Cu-Nb复合线材的微观组织与织构演变,并利用纳米压痕研究了线材硬度随退火温度的变化规律。结果表明,在400-500 ℃退火时,Nb芯丝开始发生球化,纳米尺度Cu基体开始再结晶。退火后线材织构并没有明显变化,始终保持很强的平行于拉拔方向的<111>_Cu//<110>_Nb丝织构。分别用复合材料混合法则和约束层滑移(Confined layer slip, CLS)模型对纳米硬度值进行拟合。Nb芯丝球化前线材硬度可以通过约束层滑移模型拟合,退火温度超过800 ℃时硬度则符合复合材料混合定律。

Abstract:

Microstructure and texture evolution of as-drawn and annealed Cu-Nb microcomposite wires were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The variation of hardness of the wires with the annealing temperature was investigated using nanoindentation. The results show that the Nb fibers begin to spheroidize and the nanoscale Cu matrix to recrystallize when annealed at 400-500 ℃. The texture of wires changes insignificantly after annealing, maintaining a strong <111>_Cu//<110>_Nb fiber texture along the wire axis. Nanohardness was analyzed by the rule of mixtures and the confined layer slip (CLS) model, respectively. The nanohardness is fitted well with the CLS model before the spheroidization of the Nb fibers, while the nanohardness conforms to the rule of mixtures when the annealing temperature is above 800 ℃.