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利用光学显微镜、扫描电镜和电子探针研究了H13钢中初生碳氮化物高温分解时的形貌、尺寸、成分变化规律.原始初生碳氮化物主要为10~30μm的长条状(V_x,Mo_(1-x))(C_y,N_(1-y))及少量方形的(Ti_x,V_(1-x))(C_y,N_(1-y)).在1200℃保温2.5 h后碳氮化物边缘变为凹凸不平的锯齿状,然后形成细小的分解颗粒,10 h后碳氮化物平均长度减小为12.9μm,主要为(Ti_x,V_(1-x))(C_y,N_(1-y)).当经过1250℃×5 h保温后87%的碳氮化物发生分解,(V_x,Mo_(1-x))(C_y,N_(1-y))溶解消失,碳氮化物长度在20μm以下,当保温时间延长到10 h后碳氮化物长度均在10μm以下,70%为方形并且93%分解形成细小颗粒,未分解的碳氮化物为(Ti_x,V_(1-x))(C_y,N_(1-y)).电子探针分析(Ti_x,V_(1-x))(C_y,N_(1-y))的分解与Fe元素扩散有关,高温时Fe在(Ti_x,V_(1-x))(C_y,N_(1-y))中含量逐渐增加而Ti、V减少,优先在边部曲率半径较小部位或缺陷处分解,形成0.1~1μm的细小分解颗粒,并由外向内以区域溶解方式使原始碳氮化物逐渐消失.双亚点阵模型分析两种碳氮化物的平衡溶解温度和组成有关,试样中大部分(Ti_x,V_(1-x))(C_y,N_(1-y))平衡溶解温度在1200~1246℃之间,与实验吻合较好.
The morphologies, sizes and compositions of primary carbonitride in H13 steel were studied by means of optical microscope, scanning electron microscopy (SEM) and electron probe.The primary primary carbonitrides were mainly composed of 10 ~ 30μm long strips (V_x, Mo_ (1-x) (C_y, N_ (1-y)) and small amount of square (Ti_x, V_ (1-x)) (C_y, N_ (1-y) After 10 h, the average length of carbonitride decreases to 12.9 μm, which is mainly composed of (Ti_x, V_ (1-x)) (C_y, N_ (1- (V_x, Mo_ (1-x)) (C_y, N_ (1-y)) disappeared when 87% of carbonitrides decomposed after 1250 ℃ × 5 h incubation. The length of carbonitride was (Ti_x, V_ (1-x)) (Ti_x, V_ (1-x)), and the carbonitride is decomposed into fine particles with 70% of square and 93% C_y and N_ (1-y)). The decomposition of Fe_ (1_x) and V_ (1_x) (C_y, N_ (1-y) (1-x)) (C_y, N_ (1-y)), the content of Ti and V decreases gradually, and it is preferentially decomposed at a site or a defect with a small radius of curvature of the edge to form a fine And the original carbonitrides disappear gradually from the outside to the inside by means of regional dissolution.Double sublattice model was used to analyze the equilibrium dissolution temperature and composition of the two carbonitrides, and most of the samples (Ti_x, V_ (1- x)) (C_y, N_ (1-y)) equilibrium dissolution temperature between 1200 ~ 1246 ℃, and the experimental agreement is good.