Ag-SnO_2复合材料变形断裂分析

Analyses of Ag-SnO_2 Material Fracture from Deformation

采用ＳＥＭ、ＥＤＳ及ＯＭ 方法， 对Ａｇ － ＳｎＯ２ 的变形断裂样品进行研究， 结果表明，该材料加工变形困难、硬度高， 不易通过热处理回复再结晶的主要原因是ＳｎＯ２ 粒度较细（１μｍ） ， 阻碍了金属变形时的滑移行为。同时， 由于ＳｎＯ２ 密度较低， 在相同质量比的情况下， 体积分数较高。因此， 颗粒强化效果明显， 在Ａｇ － ＳｎＯ２ 的冷变形过程中， 材料内部存在位错及显微孔洞应力松弛现象， 使硬化曲线呈起伏状平缓上升。对强化增量贡献最大的是由粒子掺入导致的位错增值及晶粒细化效应。对断口的ＳＥＭ、ＥＤＳ分析还表明： Ａｇ －ＳｎＯ２ 材料的断裂类型为韧性断裂， 并且断裂沿塑性较好的Ａｇ

The samples fractured of Ag-SnO 2 deformation have been investigated by SEM,EDS,and OM.The work released that the fact that the difficulty with deformation process,higher hardness,and difficulty of recrystallization by thermal treatment resulted from that finer SnO 2 particles which restricted the sliding during material deformation,while that higher volume percent because of lower density of Ag-SnO 2.Therefore,during Ag-SnO 2 cold deformation,both the dislocation existed within the material and the stress relaxation from microhole leaded the hardening curves raising gently.Both the dislocation increment introduced by particle permeation and the effect introduced by grain fining made the greatest contribution to the strengthening.SEM,EDS analyses on fracture faces also showed that the fracture type of Ag-SnO 2 material attributed a ductile one,and the cracks were growing up along the better plastic Ag-matrix.