在铝液中热循环H13钢的软化行为  

Softening Behavior of H13 Steel by Thermal Cycling between Molten ADC12 Al-alloy and Spray Cooling Chamber

作　　者：娄伟冬 赵海东[1] 王果 LOU Weidong;ZHAO Haidong;WANG Guo(National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学国家金属材料近净成形工程技术研究中心,广州510640

出　　处：《材料研究学报》2024年第8期593-604,共12页Chinese Journal of Materials Research

基　　金：广东省重点领域研发计划(2020B010184002)。

摘　　要：将H13钢在ADC12铝液(670~730℃)中热循环(1000~10000 cycles)实验,研究其微观组织的演变和硬度的变化,并基于固态相变动力学理论分析了硬度变化的定量模型。结果表明,在铝液中热循环H13钢发生软化。在热循环的前期基体的软化主要源于位错密度的降低,随着热循环次数的增加软化源于碳化物的粗化、马氏体板条块的宽化以及亚晶粒的长大。在不同的热循环期间,铝液温度的提高使基体的软化加快。依据固态相变动力学方程计算出H13钢的相变激活能为200.78 kJ/mol,与合金元素Cr、V以及Mo在铁素体中的扩散激活能相近。这表明,H13钢的软化速率取决于这些元素的扩散。The thermal cycling(1000~10000 cycles)testing of H13 steel between molten ADC12 Alalloy(670~730oC)and spray cooling chamber was conducted in this paper.The microstructure evolution and hardness change of H13 steel were studied against the cycling process,and then,a quantitative model of hardness change was established based on the kinetics of solid phase transformations theory.The results indicate that H13 steel undergoes softening along with the thermal cycling.At the beginning of the cycling,the softening of the matrix is mainly due to the decrease of dislocation density.With the increase of the cycling times,the softening at the middle and late stages was mainly due to the coarsening of carbides,the broadening of martensite lath and the growth of sub-grains.During different cycling tests,increasing the temperature of the molten Al-alloy may accelerate the softening of the matrix.According to the kinetics equation of solid phase transformations,the calculated phase transformation activation energy of the H13 steel is 200.78 kJ/mol,which is similar to the diffusion activation energy of alloy elements Cr,V,and Mo in ferrite,indicating that the softening rate of H13 steel depends on the diffusion of these elements.

关 键 词：金属材料 H13钢 热循环 微观组织 硬度 相变动力学 

分 类 号：TG142[一般工业技术—材料科学与工程]