P92钢中拉弗斯相的尺寸测量及其长大规律的动力学模拟计算  

Measuring Laves Phase Particle Size and Thermodynamic Calculating Its Growth and Coarsening Behavior in P92 Steels

作　　者：姚兵印[1] 周荣灿[1] 范长信[1] 李太江[1] John Hald 

机构地区：[1]西安热工研究院有限公司,陕西省西安市710032 [2]丹麦技术大学机械工程学院

出　　处：《中国电机工程学报》2010年第8期94-100,共7页Proceedings of the CSEE

摘　　要：拉弗斯相(Laves相)是超超临界机组用新型耐热钢——P92钢的重要析出相之一,对其在扫描电镜下的尺寸测量方法进行介绍,并采用热力学软件计算分析其长大规律。在扫描电镜下形成的背散射图像的原子序数差及二次电子像能够清晰地辨别出Laves相和碳化物(M23C6),这是Laves相测量方法的基础。通过与透射电镜对比,表明扫描电镜是分析Laves相的优先使用的方法。测量了3种P92钢中Laves相颗粒尺寸,研究表明Laves相颗粒尺寸越小,数量越多,材料的抗蠕变性能越好,相同条件下蠕变断裂时间越长。采用热力学计算程序DICTRA进行数值模拟,结果表明,所采用的Laves相长大模型能够很好地模拟Laves相的长大规律,但长时间(650℃、20000h和600℃、50000h)后应采用奥斯特瓦尔德长大规律(Ostwald ripening)来分析Laves相。The growth of Laves phase particles in three kinds of P92 steels were investigated. Laves phase particles can be easily separated and distinguished from the matrix and other particles by atom number contrast using comparisons of the backscatter electrons （BSE） images and the secondary electrons （SE） images in scanning electron microscope （SEM）. The smaller Laves phase particle size results in higher creep strength and longer creep exposure time at the same conditions. DICTRA software was used to model the growth and coarsening behavior of Laves phase in the three P92 steels. Good agreements were attained between measurements in SEM and modeling by DICTRA. Ostwald ripening should be used for the coarsening calculation of Laves phase in P92 steels for time longer than 20 000 h and 50 000 h at 650℃ and 600℃, respectively.

关 键 词：P92钢 蠕变 LAVES相 扫描电镜 动力学模拟 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程] TG142[一般工业技术—材料科学与工程]