摘要
通过JMat Pro软件模拟计算2507SDSS热力学平衡相图、CCT和TTT曲线确定热处理工艺,采用扫描电镜、X射线能谱仪、万能拉伸机和硬度计等研究冷却速率对2507 SDSS微观组织和力学性能的影响。结果表明,当冷却速率小于900℃/min时,σ相在α/γ相界和α/α相界处形核析出并朝着α相区域生长,冷却速率越小,σ相形核析出速率越快,σ相体积含量越大;当冷却速率大于900℃/min时,微观组织无σ相析出,仅由α相和γ相组成,σ相导致材料强塑积快速下降,σ相体积含量增大,材料抗拉强度和硬度上升,延伸率和截面收缩率下降,拉伸试样断口断裂形式由韧性断裂逐渐转变为脆性断裂。
JMat Pro software is used to simulate and calculate thermodynamic equilibrium phase diagram,CCT and TTT curves of 2507 SDSS to determine the heat treatment process.The scanning electron microscope,the x-ray energy spectrometer,the universal tensile machine and the hardness tester are applied to research the effect of cooling rate on microstructure and mechanical properties of 2507 SDSS.The results show that when the cooling rate is less than 900℃/min,σphase precipitate at α/γ phase boundaries and α/α grain boundaries and grow towards intoαphase region.The smaller the cooling rate,the faster nucleation and precipitate rate and the larger volume content of σ phase.When the cooling rate is higher than 900℃/min,there are α phase and γ phase in microstructure without σ phase.σphase leads strength-ductility balance decline seriously of material.With the increase of the volume content of σ phase,the tensile strength and hardness of material increase,while the elongation and section shrinkage decrease.The fracture mode of tensile specimens gradually changes from ductile fracture to brittle fracture.
作者
郑添义
陈宁
ZHENG Tianyi;CHEN Ning(College of Marine Equipment and Mechanical Engineering,Jimei University,Xiamen 361000,Fujian,China)
出处
《船舶工程》
CSCD
北大核心
2021年第4期106-112,共7页
Ship Engineering
基金
国家基金培育项目(ZP2020045)。
