B对Fe-Cr-B-C合金热处理后显微组织和强韧性的影响  

Effect of Boron on the Microstructure and StrengthToughness of Fe-Cr-B-C Alloy after Heat Treatment

作　　者：李阳 赵广迪 臧喜民[1,2] 姜昊源 王兆宇 Li Yang;Zhao Guangdi;Zang Ximin;Jiang Haoyuan;Wang Zhaoyu(School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,China;School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China)

机构地区：[1]辽宁科技大学材料与冶金学院,鞍山114051 [2]沈阳工业大学材料科学与工程学院,沈阳110870

出　　处：《特殊钢》2024年第5期25-33,共9页Special Steel

基　　金：辽宁科技大学创新创业项目(No.S202310146008);国家自然科学基金项目(No.52174317)。

摘　　要：为了探索调控Fe-Cr-B-C合金强韧性匹配的新方法,研究了B对其热处理后显微组织、硬度及冲击韧性的影响。经1 050℃空淬处理后,在低w[B](0.000 6%)合金的枝晶间析出大量极细二次碳硼化物,在中w[B](0.51%)和高w[B](2.89%)合金基体中析出弥散的二次碳硼化物。随B含量增加,二次碳硼化物的颗粒度增大,颗粒密度降低。经1 050℃空淬+500℃回火处理后,三种B含量合金中的二次碳硼化物均增多,且析出区域扩大。低B合金的枝晶干为粗大板条马氏体,枝晶间由针状马氏体、高密度二次碳硼化物及少量凝固析出相构成,其冲击韧性最佳,洛氏硬度居中;中B合金主要由弥散分布着二次碳硼化物的针状马氏体基体以及网状硼碳化物构成,其洛氏硬度最高,冲击韧度居中;高B合金由弥散分布着少量二次碳硼化物的γ基体及更致密的网状硼碳化物构成,其洛氏硬度和冲击韧度均最低。另外,中B和高B合金的网状硼碳化物发生了局部断网,导致其冲击韧性较铸态下明显提高。In order to explore new methods for improving the strength-toughness matching of Fe-Cr-B-C alloy, the effect of B content on its microstructure, hardness, and impact toughness after heat treatment were investigated. The results showed that after air-cooling quenching at 1 050 ℃, a large amount of extremely fine secondary carbon-borides precipitated in the interdendritic region of low-B(0. 000 6%) alloy, and fine dispersed secondary carbon-borides precipitated in the matrix of intermediate-B(0. 51%) and high-B(2. 89%) alloys. As the B content increased, the size of secondary carbon-borides increased but the particle density decreased. After air-cooling quenching at 1 050 ℃ plus tempering at 500 ℃, the number of secondary carbon-borides increased and the precipitation region expanded. For the low-B alloy, the dendrite arm was composed of coarse lath-like martensite, and the interdendritic region was composed of acicular martensite, high-density secondary carbon-borides and a small amount of solidification precipitates. For the intermediate-B alloy, the microstructure was composed of acicular martensite matrix with dispersed secondary carbon-borides, and network boron-carbides. For the high-B alloy, the microstructure was composed of γ matrix with a small amount of dispersed secondary carbon-borides, and denser network boron-carbides. The low-B alloy possesses the highest impact toughness and moderate Rockwell hardness. The intermediate-B alloy possesses the highest Rockwell hardness and moderate impact toughness. The high-B alloy possesses the lowest Rockwell hardness and impact toughness. Compared with the as-cast state, the solidification precipitates dissolved slightly after the quenching and tempering treatment, which resulted in the local rupture of netlike boron-carbides in intermediate-B and high-B alloys. Thus, after air-cooling quenching at 1 050 ℃plus tempering at 500 ℃, the impact toughness of intermediate-B and high-B alloys improved obviously.

关 键 词：Fe-Cr-B-C合金 B 热处理 显微组织 二次碳硼化物 强韧性 

分 类 号：TG113.1[金属学及工艺—物理冶金]