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对高温固溶后的SAF2906双相不锈钢进行时效处理,固溶温度为1 200℃,保温时间1h,时效温度为650℃、700℃、750℃、800℃、850℃、900℃、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,采用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。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先增大后减小,在约850℃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相比有相似之处,形核位置大部分出现在α-铁素体内部和γ-奥氏体/α-铁素体两相之间,但有部分析出相出现在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,当保温时间达到5min时,σ相比例<5%,此时伸长率可达1 000%。
The aging treatment of high temperature solid solution SAF2906 duplex stainless steel is carried out at a solution temperature of 1 200 ℃ for 1h, aging temperature of 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, The morphology of precipitated phases in SAF2906 duplex stainless steel was observed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The content of each chemical element in precipitated phase was measured by EDS spectroscopy. Machine samples were heated at constant temperature, the analysis of changes in sample elongation at different experimental temperatures. The results show that the precipitation of σ phase increases first and then decreases with the increase of aging temperature and reaches the maximum at about 850 ℃. The distribution of σ precipitation phase in SAF2906 duplex stainless steel compared with the same type of duplex stainless steel There are similarities. Most of the nucleation sites appear between the α-ferrite and γ-austenite / α-ferrite phases, but some precipitates appear in the γ-austenite. When the deformation temperature is 850 ℃ and 900 ℃, the elongation of σ phase can reach 382% and 538%, respectively. When the temperature is 950 ℃, with the holding time , The proportion of σ phase in the sample decreases continuously and the sample elongation increases continuously. When the holding time reaches 5 min, the ratio of σ phase is less than 5%, and the elongation can reach 1 000%.