应变时效过程中析出相界面Al/θ~′的能量响应  

Energetics response to precipitates interface Al/θ' under strain aging

作　　者：罗康[1] 江勇[1,2] 易丹青[1,2] 傅上[1] 臧冰[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《中国有色金属学报》2013年第10期2785-2791,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51071177);国家重点基础研究发展计划资助项目(2012CB619506)

摘　　要：基于第一性原理密度泛函方法,计算研究Al/θ′共格界面对应变时效参数的能量响应,综合讨论外加单向应变、时效温度以及Cu化学活度对界面形成能的影响作用。结果表明:θ′相的界面能随温度的升高而增大,当温度从298 K增加到498 K时,大尺寸的θ′相界面能(γAl/θ′)增大约2.3%,而小尺寸的富铜θ′相界面能(γAl/θ′(Cu-rich))增大约7.6%;在相同温度和应变下,小尺寸的富铜θ′相界面能总是比大尺寸θ′的相界面能低约10%。在室温下,当应变从0增加到2%时,富铜θ′相界面能最大降低约9.2%;不同的应变方式(压缩或拉伸、垂直或平行界面方向)对各类型θ′相界面能的作用效果有所不同,由此影响到其在基体中的析出方式,这应该是应变时效的主要机制之一。Based on first-principles, the potential effects of coherent AI/θ＇ interfaces under the response to external strains were calculated, and the effect of the uniaxial strain, aging temperature and Cu activity on the interfacial energies of both stoichiometric and Cu-rich AI/θ＇ interfaces energies were investigated. The results show that the interracial energies 0＇ phase always increase with temperature increasing, the larger size interface energy （YAVe） and smaller size interface energy （ γ_AI/θ＇ （Cu-rich）） increase by about 2.3% and 7.6%, respectively, as the temperature increases from 298 to 498 K. Under the same temperature and strain states, γ_AI/θ＇（cu-nch） is always lower than γ_AI/θ＇ by about 10%. For a parallel tensile strain of 2% at room temperature, γ_AI/θ＇（Cu-rich） decreases the most by up to about 9.2%. The different strain signs （compressive or tensile） and directions （parallel or vertical） have different influences on the interface energies, and can affect the orientation preference of 8＇ precipitates in the matrix. This may be one major mechanism for stain/stress aging.

关 键 词：AL θ'界面 界面能 应力-应变时效 第-性原理 

分 类 号：TG111.5[金属学及工艺—物理冶金]