(中南大學 材料科學與工程學院，長沙 410083)
摘 要: 采用金相顯微鏡和掃描電鏡研究Cu-9Ni-2.3Sn(C72500)合金經剪切變形后合金切面的微觀組織以及隨后在550 ℃退火2 h后切面的組織變化。結果表明：經剪切變形后，切面處形成一種獨特的帶狀變形孿晶和蜂窩狀變形組織，且存在擠壓、扭折等多種變形機制的作用；合金在550 ℃退火2 h后，切面出現許多再結晶晶粒，且在承受剪床切口的一邊再結晶晶粒非常細小，相當于冷軋變形80%后的再結晶晶粒尺寸。根據這種現象，以異步軋制和板材連續(xù)剪切變形技術(C2S2)為基礎，提出一種金屬板材利用剪切變形配以適當熱處理來細化晶粒的構想，有望在材料加工領域實現新的突破。
關鍵字: C72500合金；剪切變形；變形帶；細化晶粒
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract: The shear plane microstructures of Cu-9Ni-2.3Sn(C72500) alloy after shearing deformation and then annealed at 550 ℃ for 2 h were observed by OM and SEM. The results show that some twin crystals and honeycomb structures appear in the shear plane and many kinds of deformation mechanism exist such as extruding, kinking and so on. When annealed at 550 ℃ for 2 h, the recrystal gains are observed in the shear plane. Especially the side receives the cut of guillotine, the size of recrystal grain is very thin, corresponding with the recrystal grains obtained by cold rolling at 80% deformation rate. Based on this phenomenon, associating with asynchronous rolling and confined strip shearing technology, a method was proposed to refine the grains in metal sheets by using shearing deformation and annealing sample at suitable temperature to obtain ultra fine grains. Hopefully this would prompt the development of material processing area.
Key words: C72500 alloy; shearing deformation; deformation band; refining grain
