A508-Ⅲ钢小尺寸试样的拉伸尺寸效应及其归一化模型研究  

Size Effect and Its Normalization Model of A508-Ⅲ Steel Small Size Specimen

作　　者：忻胜民 黎军顽[1] 钟巍华[2] 杨万欢 宁广胜[2] 杨文[2] XIN Shengmin;LI Junwan;ZHONG Weihua;YANG Wanhuan;NING Guangsheng;YANG Wen(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;Reactor Engineering Technology Research Institute,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444 [2]中国原子能科学研究院反应堆工程技术研究所,北京102413

出　　处：《原子能科学技术》2022年第12期2698-2706,共9页Atomic Energy Science and Technology

基　　金：大型先进压水堆核电站重大专项(2018ZX06002008)。

摘　　要：设计了系列A508-Ⅲ钢小尺寸试样,开展了不同热处理温度和不同厚度下小尺寸试样的室温拉伸测试,分析了小尺寸试样尺寸效应的影响机理。结果表明,随着奥氏体化温度由900℃升高到1 000℃,A508-Ⅲ钢的晶粒尺寸由18.12μm增加到33.21μm;不同热处理温度和不同厚度A508-Ⅲ钢小尺寸试样的拉伸力学性能呈现明显的尺寸效应;随着晶粒尺寸的细化,产生了晶粒尺寸效应,而随着小尺寸试样厚度的减小,产生了特征尺寸效应。同时,引入了能综合描述小尺寸试样晶粒尺寸效应和特征尺寸效应的关键参数λ,构建了考虑尺寸效应的力学本构模型,获得了小尺寸试样与标准试样的屈服强度和抗拉强度归一化模型,并基于试验结果验证了归一化模型的准确性和可靠性,以期为力学性能的换算提供借鉴。The nuclear reaction pressure vessel has induced radioactivity after service, and small size specimens are required to be used for safety and improvement of material utilization. However, due to the submillimeter size, size effects will inevitably occur. It will result in differences in mechanical property test results in comparison to the standard specimens, and hinder the practical applications. Thus, this paper aims to reveal the tensile size effect mechanism of small size specimens of A508-Ⅲ steel which are used for nuclear reaction pressure vessels, and to establish the relationship between sample size and mechanical properties. The thickness of the small size specimens was changed based on Small Specimen-Japan(SS-J), and the different grain sizes were obtained by changing the heat treatment process. In order to avoid the influence of the surface state on the test results, the small size specimens were processed by electrical discharge machining with a slow cutting speed, and then polished. The mechanical properties of small size specimens with different thicknesses and grain size values were tested at room temperature. Before the tensile test, a mixture of alumina and alcohol was sprayed on the surface of the small size specimens to create speckles and facilitate the extensometer to identify the deformation of the gauge length of the small size specimens. The results show that, as the austenitizing temperature increases from 900 ℃ to 1 000 ℃, the grain size of A508-Ⅲ steel increases from 18.12 μm to 33.21 μm. The mechanical property of small size specimens with different heat treatment temperatures and different thicknesses exhibits an obvious size effect. As the grain size is refined, the grain size effect is produced and the internal grain boundary model can better explain its mechanism. As the thickness of the small size specimen decreases, the feature size effect is produced and the surface layer model can better explain its mechanism. In addition, a key parameter λ comprehensively described

关 键 词：A508-Ⅲ钢 小尺寸试样 尺寸效应 力学本构模型 归一化模型 

分 类 号：TG115.52[金属学及工艺—物理冶金] TM623[金属学及工艺—金属学]