Mo-C棒的横向弯曲性能  

Transverse bending property of molybdenum-carbon bars

作　　者：陈畅[1] 汪明朴[1] 谭望[1] 郭明星[1] 张娟[1] 白超[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2009年第1期129-134,共6页Journal of Central South University:Science and Technology

基　　金：国家"863"计划资助项目(2006AA03Z517);湖南省自然科学基金资助项目(05JJ30095)

摘　　要：采用弯曲性能测量、晶内及晶界的显微硬度测试、金相显微镜、扫描电镜观察等方法,对不同状态下的Mo-C棒横向弯曲性能及组织进行研究。研究结果表明:Mo-C棒再结晶开始温度在950℃左右,在1200℃时基本形成了等轴晶组织;当退火温度低于1200℃时,随着退火温度的升高,合金的横向弯曲性能逐渐提高,在1100～1200℃时,合金的横向弯曲延伸率最高,达到5%。添加碳后,合金的晶界显微硬度比合金的晶内显微硬度高150MPa左右;纯钼的断裂方式以沿晶断裂为主,添加碳后,由于合金的晶界强度得到提高,合金的断裂方式变成以穿晶断裂为主,断口上有大量的解理面,具有明显的河流状花样和解理台阶,且塑性越好的断口,撕裂岭也越多;当添加的碳含量偏高时,在晶界处产生了大颗粒的碳化物,这种大颗粒的碳化物会降低合金的塑性。The transverse bending property and microstructure of molybdenum-carbon bars in different conditions were investigated by bending property measurement, the measurement of microhardness in both grain and grain boundary, optical microscopy（OM）, and scanning electron microscopy （SEM）. The results are as follows： The start recrystallization temperature of Mo-C is about 950℃ and the process is finished around 1 200℃, and during this process, the transverse bending property is gradually improved and the elongation percent of the transverse bending reached max value （about 5%） at 1 100-1 200℃. After the addition of carbon, the microhardness in the grain boundary is about 150 MPa higher than that in the grain. The fracture type of pure Mo is intergranular fracture, the grain boundary strength of Mo-C alloy is strengthened due to the addition of carbon and the fracture type is changed to transgranular fracture, transcrystalline fracture and a large number of cleavage planes and steps are observed on the bending fracture surface. But if the carbon content is too high, the carbide precipitation will be severe at grain boundaries and is deleterioated to the ductility of the alloy.

关 键 词：Mo-C棒 横向塑性 沿晶断裂 穿晶断裂 

分 类 号：TG146.412[一般工业技术—材料科学与工程]