时效温度对GX40CrNiSi25-12奥氏体耐热钢析出相的影响  

Effect of aging temperature on precipitates of GX40CrNiSi25-12 austenite heat resistant steel

作　　者：李杰 胡建文[1,2,3] 陆子彤 LI Jie;HU Jian-wen;LU Zi-tong(School of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China;Hebei Province Key Laboratory of Near-net Forming of Materials,Shijiazhuang 050018,China;Hebei Innovation Center for Superalloy Investment Casting Technology,Huanghua 061100,China)

机构地区：[1]河北科技大学材料科学与工程学院,河北石家庄050018 [2]河北省材料近净成形重点实验室,河北石家庄050018 [3]河北省高温合金熔模铸造技术创新中心,河北黄骅061100

出　　处：《材料热处理学报》2022年第1期121-130,共10页Transactions of Materials and Heat Treatment

摘　　要：为了研究高温时效对GX40CrNiSi25-12奥氏体耐热铸钢析出相的影响,采用JMatPro软件模拟其在不同温度下的平衡相图和析出相随温度的变化,通过光学显微镜、扫描电镜和能谱分析等研究了不同温度时效处理对试验钢的析出相的形态、大小、析出位置及硬度的影响。结果表明:850℃时效24 h后,大量细小颗粒状的M_(23)C_(6)碳化物在基体奥氏体晶粒内析出,在奥氏体晶粒内还发现有少量细针状σ相析出,同时在枝晶处出现密集分布的块状σ相,试验钢的硬度显著升高,达到最大值;950℃时效24 h后,晶内析出相减少,颗粒状M_(23)C_(6)碳化物偏聚在枝晶附近析出,且出现集聚和长大,导致试验钢的硬度显著下降;1050℃时效24 h后,枝晶骨架中的一次碳化物基本溶入基体中,在晶界处分散的颗粒状M_(23)C_(6)相呈链状分布,无σ相存在。In order to study the effect of high temperature aging on precipitated phase of GX40CrNiSi25-12 austenitic heat-resistant cast steel,the equilibrium phase diagram at different temperatures and the change of precipitated phase with temperature of the experimental steel were simulated by JMatPro software.The effects of aging treatment at different temperatures on morphology,size,precipitation position of the precipitated phase and the hardness of the experimental steel were studied by means of optical microscope,scanning electron microscopy and energy spectrum analysis.The results show that after aging at 850℃for 24 h,a large number of fine granular M_(23)C_(6) carbides precipitate in the austenite grains,a small amount of fine needle-likeσphase is found in the austenite grains,and at the same time,dense massiveσphase appears at the dendrite,which lead that the hardness of the experimental steel increases significantly and reaches the maximum.After aging at 950℃for 24 h,the number of precipitates in the austenite grain decreases,the granular M_(23)C_(6) carbides are segregated and precipitated near the dendrite,and the agglomeration and growth occur,resulting in a significant decrease in the hardness of the experimental steel.After aging at 1050℃for 24 h,the primary carbides in the dendrite skeleton basically dissolve into the matrix,and the granular M_(23)C_(6) phases dispersed at the grain boundary present chainlike distribution,and there is no existence ofσphase.

关 键 词：奥氏体耐热铸钢 高温时效 析出相 热力学模拟 微观组织 

分 类 号：TG142.7[一般工业技术—材料科学与工程]