摘要
为了研究硅在马氏体型热作模具钢中的作用机理,冶炼了一种高硅马氏体型热作模具钢SDH3.借助TEM和3DAP微观分析设备研究了SDH3钢的显微组织特征以及合金元素的分布特点.实验结果表明:适当提高硅含量能有效增加和稳定H13钢中残余奥氏体;残余奥氏体可细化马氏体板条,提高SDH3钢的强韧性;硅在碳化物周围富集,降低了碳在铁素体中的扩散速率,阻碍碳化物的长大和粗化,有效地提高了SDH3钢的回火稳定性.另外,由于硅降低碳的析出阀值而提高了碳的扩散阀值,在回火时促进碳化物提前从α-Fe晶格间隙弥散析出而又不易聚集长大,也增加了钢的回火稳定性.
A high silicon martensitic hot work steel SDH3 was prepared to study the effect of silicon in the high silicon martensitic hot work steel. The microstrueture and alloy element portioning in steel SDH3 was studied by transmission electron microscopy （TEM） and three-dimensional atom probe （3DAP）, respectively. The experiment results show that an appropriate increase of silicon in the steel can efficiently increase the volume of retained austenite and make it more stable at higher temperature. The retained austenite has noticeable effect on refining martensite laths, which enhances the strength and toughness of steel SDH3. Silicon precipitates around carbide grains during temper, which consequently decreases the diffusion rate of carbon in ferrite, and as a result it effectively retards the growth and coarsening of carbide precipitations and improves the stabil- ity of steel SDH3. Moreover, Silicon decreases the critical depositing activation energy and increases the criti cal diffusing activation energy of carbon, which makes the carbides easier to deposit in advance from the interstice of α-Fe, but more difficult to coarsen during temper stage. It is also helpful to the stability of the steel.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2010年第6期772-776,共5页
Materials Science and Technology
基金
"十一五"国家科技支撑计划资助项目(2007BAE51B04)
上海市重点学科建设资助项目(S30107)
