(1. 中南大學(xué)材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué)有色金屬先進結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083)
摘 要: 通過XRD、TEM、EBSD以及拉伸試驗研究硅元素對超細晶黃銅力學(xué)性能和退火行為的影響。將Cu-20Zn和Cu-20Zn-1.2Si合金在液氮溫度(約-196 ℃)下進行軋制并進行退火處理。結(jié)果表明：與液氮軋制后Cu-20Zn合金相比，液氮軋制后Cu-20Zn-1.2Si合金的強度顯著提升，這是因為加入的硅元素使得層錯能降低，使其變形后具有細小的晶粒以及較高的位錯和孿晶密度。Cu-20Zn-1.2Si合金熱穩(wěn)定性的提升源自層錯能(SFE)的降低以及硅原子與位錯的相互作用，使得其內(nèi)部位錯運動受阻。退火后的Cu-20Zn-1.2Si合金優(yōu)異的強度和塑性的綜合力學(xué)性能源自其組織內(nèi)部細小的晶粒、形變孿晶以及大量的退火孿晶和HAGBs的共同作用。
關(guān)鍵字: 銅合金；層錯能；力學(xué)性能；孿晶；退火行為
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,
Central South University, Changsha 410083, China）
Abstract:The effect of silicon on mechanical properties and annealing behavior of ultrafine-grained (UFG) brasses was investigated in Cu-20Zn and Cu-20Zn-1.2Si alloys by X-ray diffraction (XRD), transmission electron microscope (TEM), electron back scattered diffraction (EBSD) and tensile tests. These two brasses were rolled at cryogenic temperature (about -196 ℃) up to different rolling strains. The results show that the significant improvement of strength in Cu-20Zn-1.2Si alloy is attributed to the formation of fine grains and high densities of dislocations and deformation twins by decreasing the stacking fault energy (SFE). Thermal stability of Cu-20Zn-1.2Si alloy is enhanced due to the reductions of dislocation mobility and grain boundaries migration during annealing by decreasing of SFE and addition of Si. Fine grains, deformation twins and abundant annealing twins are introduced into Cu-20Zn-1.2Si alloy by decreasing the SFE, resulting in a superior strength and ductility combination.
Key words: Cu alloy; stack fault energy; mechanical property; twins; annealing behavior
