350℃下长期时效对17-4PH不锈钢动态断裂韧性的影响  

Effect of Long-Term Aging at 350 ℃ on Dynamic Fracture Toughness of 17-4PH Stainless Steel

作　　者：王均[1] 邹红[2] 伍晓勇[2] 杨宏山[1] 邱绍宇[2] 沈保罗[1] 

机构地区：[1]四川大学材料科学与工程学院,四川成都610064 [2]中国核动力研究设计院,四川成都610041

出　　处：《原子能科学技术》2006年第2期243-248,共6页Atomic Energy Science and Technology

基　　金：核燃料及材料国防科技重点实验室基金资助项目(51481080104ZS8501)

摘　　要：利用示波冲击试验系统研究反应堆用17-4PH马氏体不锈钢在使用温度(350℃)下长期(约11 000 h)时效过程冲击性能和动态断裂韧度的变化规律,并用扫描电镜观察分析不同时效时间的CharpyⅤ型缺口试样(CVN)的断口形貌。结果表明:该马氏体不锈钢在350℃长期时效的过程中,随着时效时间的延长,其塑性变形能EPL和撕裂能ETE以及冲击功Et均随时效时间的延长而逐渐下降。根据示波冲击曲线获得了该钢的动态断裂韧度KId,其动态断裂韧度也随时效时间的延长而逐渐下降,并在试验的初始阶段下降很快,在试验的中后期下降较为缓慢。另外,该不锈钢的CVN冲击试样断口形貌随着时效时间的延长由韧性断裂机制的韧窝断裂为主向脆性断裂机制的准解理断裂和穿晶断裂为主变化。这些均说明,随着时效时间的延长,该材料的韧性降低,发生了脆化,且脆化主要发生在试验的初始阶段。The variation of impact performance with the extension of aging time on the type of 17-4PH stainless steel at 350℃ was studied in the paper, and the variation of dynamic fracture toughness and fractographys of the type stainless steel for various holding time at this temperature were also researched by instrumental impact test and scanning electron microscope. All results indicate that the plastic deformation energy （EEL）, tearing energy （ETE）, absorbed-in-fracture energy （Et） and dynamic fracture toughness （Kid） of this type alloy are decreased with the continuation of time at 350℃. The Kld falls fast at the forepart of aging test and then slowly. It shows that the toughness of the alloy is degraded and the degradation is mainly taken place at the forepart of aging test. The fractography of this alloy is changed from dimple fracture into cleavage fracture and inter-granular rapture with the extension of aging time. Those show that the fracture toughness of this alloy has de,traded with the extension of aging time at 350℃.

关 键 词：17-4PH不锈钢 等温时效 示波冲击实验 动态断裂韧度 冲击断口剪切面积百分比 

分 类 号：TL395.6[核科学技术—核技术及应用]