机械球磨3%C-Cu复合粉末的微观组织

为了获得具有良好微观组织的C-Cu复合粉末,以利于后续的压制、烧结和挤压等工艺,用机械球磨方法制备了3%C-Cu(质量分数)复合粉末.运用扫描电镜、背散射和X射线衍射等分析手段研究了该复合粉末的微观组织随球磨时间的演变规律.实验结果表明,随着机械球磨时间的增加,Cu颗粒由树枝状转变为层片状、块状,最后转变为近球形.球磨2 h,复合粉末中的石墨衍射峰消失.随着球磨的进行,复合粉末中Cu的微观应变逐渐增大.经3 h的机械球磨获得了晶粒尺寸约为20 nm的Cu纳米晶,说明该方法可以有效地细化晶粒组织.

Microstructures of 3%C-Cu composite powders prepared by mechanical milling

To obtain C-Cu composite powders with excellent microstructures,which are beneficial to such subsequent processes as pressing,sintering and extrusion,3%C-Cu(mass percent) composite powders were prepared by mechanical milling.Their microstructures dependent on milling time were investigated with the scanning electron microscopy(SEM),back-scattered electron images and X-ray diffraction(XRD).The results show that by increasing the milling time,the particle shape of Cu changes from dentritic to laminal,then to nubby and to near-spherical finally.The diffraction peak of graphite disappears after mechanical milling for 2 h.The microstrain of Cu in composite powders increases while lengthening the milling time.The grain size of Cu in composite powders is about 20 nm after milling for 3 h,which confirms that the grain can be refined effectively with this technique.