摘要
对高温固溶之后的SAF2906双相不锈钢进行时效处理,固溶温度为1200℃,保温时间1h,时效温度为650℃、700℃、750℃、800℃、850℃、900℃和950℃,采用扫描电镜(SEM)、X射线衍射(XRD)以及透射电镜(TEM)等方法观察SAF2906双相不锈钢中析出相的形态,用EDS能谱测量析出相中各化学元素的含量,通过恒温拉伸机对试样进行恒温拉伸,分析在不同实验温度下试样伸长率的变化。实验结果表明,在本实验条件下,σ相的析出量随时效温度的升高呈现先增大后减小的趋势,在850℃左右达到最大,SAF2906双相不锈钢中的σ析出相分布规律与同类型双相不锈钢有相似之处,形核位置大部分在α-铁素体内部和γ-奥氏体/α-铁素体两相之间,部分析出相出现在γ-奥氏体内部;σ相在超塑拉伸过程变形后期容易导致断裂,在变形温度为850℃与900℃时,试样伸长率分别可以达到382%和538%,当温度为950℃时,随着保温时间的延长,σ相在试样中的比例不断下降,同时试样伸长率不断上升,当保温时间长于5min,σ相比例下降到5%以下,此时伸长率可达1000%。
The samples of SAF2906 duplex stainless steel were aged at 650℃,700℃,750℃,800℃,850℃,900℃ and 950℃for 1h,respectively,after high temperature solution treatment.Then the morphology ofσ-phase in aged SAF2906 duplex stainless steel was studied by means of scanning electron microscopy（SEM）、X-ray diffraction（XRD）and transmission electron microscopy（TEM）,the chemical composition of theσ-phase was studied by X-ray energy dispersive spectrometry（EDS）,and the plastic elongation was tested on an isothermal tensile machine under different temperatures.The results indicated that the amount ofσphase in SAF2906 duplex stainless steel increased firstly and then decreased with the increase of aging temperature,the maximum volume fraction was observed after aging treatment at 850℃.Theσprecipitation formed insideδ-ferrite and alongδ-ferrite/γ-austenite interfaces,however,with relative to other duplex stainless steel,someσphases were observed insideγ-austenite.The elongation of specimen reached to 382% and 538% at 850℃ and 900℃.Extending the heat preservation time to control the amount ofσphase could increase the elongation at 950℃.The elongation of specimen could reached 1000%after the holding time reaching5 min and volume fraction ofσphases was under 5%.
出处
《塑性工程学报》
CAS
CSCD
北大核心
2015年第5期100-107,共8页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(51334006)
