(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用金相显微镜和扫描电镜研究Cu-9Ni-2.3Sn(C72500)合金经剪切变形后合金切面的微观组织以及随后在550 ℃退火2 h后切面的组织变化。结果表明：经剪切变形后，切面处形成一种独特的带状变形孪晶和蜂窝状变形组织，且存在挤压、扭折等多种变形机制的作用；合金在550 ℃退火2 h后，切面出现许多再结晶晶粒，且在承受剪床切口的一边再结晶晶粒非常细小，相当于冷轧变形80%后的再结晶晶粒尺寸。根据这种现象，以异步轧制和板材连续剪切变形技术(C2S2)为基础，提出一种金属板材利用剪切变形配以适当热处理来细化晶粒的构想，有望在材料加工领域实现新的突破。
关键字: C72500合金；剪切变形；变形带；细化晶粒
（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
