(浙江大學(xué) 材料與化學(xué)工程學(xué)院， 杭州 310027)
摘 要: 通過冷變形拉拔結(jié)合中間熱處理制備了纖維相增強的Cu-12%Ag(質(zhì)量分數(shù))合金， 研究了變形過程對組織形態(tài)和力學(xué)性能的影響。 隨著變形程度的增加， 不連續(xù)分布的原始共晶體演變成細密的纖維束結(jié)構(gòu)， 合金強度和硬度升高。 在一定變形程度范圍內(nèi)或當共晶纖維束間距約大于150 nm時， 抗拉強度隨共晶纖維束間距的變化類似于Hall-Petch關(guān)系， 強化效應(yīng)與位錯塞積機制有關(guān)； 當拉拔變形超過一定程度或共晶纖維束間距小于約150 nm后， 合金強化速率降低并偏離Hall-Pecth關(guān)系， 強化效應(yīng)可認為與界面障礙機制有關(guān)。
關(guān)鍵字: Cu-Ag合金； 纖維組織； 強度； 硬度； 應(yīng)變率
（ College of Materials Science and Chemical Engineering, Zhejiang University, Hangzhou 310027, China）
Abstract: Cu-12%Ag filamentary composite was prepared by cold drawing and intermediate heat treatments. The evolution of filamentary microstructure and mechanical properties were investigated for the alloy at different draw ratio. With the increasing draw ratio, the as-cast eutectic colonies with a discontinuous distribution develop into fine fibrous bundles to result in the increase of the strength and hardness. As the draw ratio is in a certain strain range or the spacing of eutectic fibrous bundles greater than is 150 nm, the ultimate tensile strength dependent on the spacing of eutectic fibrous bundles is similar to the Hall-Petch relationship. The mechanism of pile-up of dislocation can be suggested to be responsible for the strengthening benefit. As the draw ratio is over a certain degree or the spacing of eutectic fibrous bundles is less than 150 nm, the strength increase becomes slow and deviates from the Hall-Petch relationship. The mechanism of athermal obstacles at the interfaces can be suggested to be responsible for the strengthening benefit.
Key words: Cu-Ag alloy; filamentary microstructure; strength; hardness; draw ratio
