不同时效时间对CB2耐热钢性能的影响.doc

本科生毕业设计 题 目 不同时效时间对CB2钢组织及性能的影响 学 院 制造科学与工程学院 专 业 材料成型及控制工程　 学生姓名 蔡 然 　 学 号 1043022063 年级 10级 　 指导教师 孙 兰 教务处制表 二 Ο 一 四 年 五 月 二 十 九 日  不同时效时间对CB2钢组织及性能的影响 专业：材料成型及控制工程 学生：蔡然 指导老师：孙兰 摘要：CB2钢属于铁素体系耐热钢，对其进行650℃下进行8h，30h，50h，80h，100h时效处理后,通过金相显微镜，SEM，TEM，拉伸测试，硬度测试实验对比分析时效后试样的显微组织和力学性能状况，在了解不同高温时效时间对CB2耐热钢的组织性能的影响的同时获得一些能够帮助提升CB2耐热钢性能的方法。结果表明，时效100h内，组织内M23C6碳化物持续析出，随着时效时间增加有长大聚集的趋势；晶界与非晶界处均有新的第二相生成，可能是M6C碳化物或新析出的M23C6碳化物，随时效时间增加数量增多，尺寸无太大变化；时效30h内，材料硬度和强度总体下降，韧性加强，可能是新相的出现导致的弥散强化造成的；时效30h-100h，由于M23C6和新相作用的差异，试样强度，硬度，韧性无明显变化规律。 关键词：时效处理；CB2耐热钢；显微组织；力学性能；M23C6碳化物，M6C碳化物 The effects of different aging time on the microstructure and properties of CB2 steel Major: engineering of material forming and controlling Name: CAI Ran Faculty adviser: SUN Lan Abstract：CB2 steel, which belongs to ferritic heat-resistant steel, would be aged at 650℃ with different aging time of 8,30,50,80,100h.. We can know not only the effects of different aging time on the microstructure and properties of CB2 steel but also some ways to improve the performance of CB2 by comparative analysis of organization and performance status after aging specimens. The results show that within the aging time of 100h, as the aging time improved, M23C6 precipitates with a tendency of growing up and accumulating consistently. The new second phase, which precipitates along boundaries and non-boundaries area, may be M6C or new M23C6, with the aging time increased, there is not much change for their size. In 30h, hardness and strength of material increased, on the contrary, the toughness decreased , this would be due to dispersion strengthening for new phases. Within 30-100h, there is no obvious pattern for the change of strength, hardness and toughness of CB2 because of the differences between M23C6 and new phases Keywords: Aging,