第二相粒子与织构对高强Cu--Ni--Si系合金薄板各向异性的影响

利用利用X射线衍射、电子背散射衍射和透射电子显微镜等手段研究了Cu-Ni-Si系合金在不同固溶温度下第二相与织构对其平面各向异性的影响.结果表明:随固溶温度的升高,合金强度和伸长率均出现先升高后降低的趋势,且存在明显的各向异性;800℃固溶时,Cu'和S'为主织构,部分形变晶粒诱发少量Brass、Goss和{011}〈511〉取向的形成,使得合金各向异性减弱;高温固溶时(≥850℃),晶粒发生完全再结晶,Cu'和S'织构强度显著增加,Brass等织构减弱甚至消失,各向异性增强;850℃固溶时效后形成δ-Ni2Si析出相,并与基体满足001]Cu//110]δ,(010)Cu//(001)δ位向关系,温度进一步增加,第二相析出体积分数降低,有利于改善材料的各向异性.

Effects of precipitates and texture on the anisotropy of high-strength Cu--Ni--Si alloy sheets

The effects of texture and precipitates on the plane anisotropy of Cu-Ni-Si alloy under different solid-solution tempera-ture conditions were investigated by X-ray diffraction, electron backscattered diffraction, and transmission electron microscopy. The results show that strength and elongation first increase and then decrease with increasing solid-solution temperature, exhibiting appar-ently anisotropy. After 800℃ solid solution, the Cu'and S' are mainly texture and the alloy has weak anisotropic properties, which correlates with the coexistence of Brass, Goss, and {011}〈511〉 orientation owing to deformed grains. Complete recrystallization can be obtained at high temperature solution (≥850℃) , the Cu' and S' texture intensity increases, whereas the Brass texture weakens and disappears and the anisotropy increases. δ- Ni2 Si precipitation is observed after 850℃ solution and subsequent aging, and the crystal orientation between the matrix and precipitates is 001] Cu//110]δ and (010) Cu//(001)δ. The fraction of nanosize precipi-tates decreases significantly with increasing temperature and this improves the anisotropy.