摘要
采用金相显微镜、扫描电镜、能谱仪、X射线衍射仪和硬度计对铁素体基球墨铸铁QT 350-22和QT 600-10进行了微观组织与断口形貌观察、相结构与成分检测和硬度测量。实验结果表明,由于两种球墨铸铁的Si含量明显不同,虽然其金相组织均为铁素体基体+颗粒状石墨+少量珠光体,但两者的力学性能和断口形貌差别很大。QT 350-22的拉伸强度较低,而冲击吸收功很高,其断口形貌呈典型的韧性断裂;QT 600-10的拉伸强度高,且延伸率较高,而冲击吸收功很低,其断口形貌呈典型的脆性断裂。随球墨铸铁中Si含量的提高,铁素体基体的Si固溶强化效果明显增加,这是由于Si原子溶入铁的晶体点阵而导致晶格畸变所致。本文的研究结果可以为优化铁素体基球墨铸铁的化学成分和铸造工艺提供重要的实验依据。
The composition,microstructure,fracture morphology,phase structure,composition test and hardness measurement were carried out by metallographic microscope, scanning electron microscopy（ SEM）,energy dispersive spectroscopy（ EDS）,X-Ray diffraction（ XRD） and microhardness tester for QT 350-22 and QT 600-10 ductile cast iron with ferritic matrix. The experimental result showed that the different of both mechanical properties and fracture morphology were very big due to their obviously different Si contents,though their microstructures all were ferritic matrix ＋ spheroidal graphite ＋ a small quantity of pearlite. The QT 350-22 had lower tensile strength,very high impact absorbing energy and its fracture was typical ductile morphology. The QT 600-10 had very high tensile strength and higher elongation,but its impact absorbing energy was very low and its fracture was typical brittle morphology. With the increasing of Si content in the ductile cast iron,the solution strengthening effect of Si in ferrite matrix markedly increased because more Si atoms dissolved in ferrite crystal lattice to result in lattice distortion.The result of this paper could provide an important experimental evidence for optimizing the chemical com-position and improving foundry technique of the ductile cast iron with ferritic matrix.
出处
《热处理技术与装备》
2017年第1期37-41,共5页
Heat Treatment Technology and Equipment
基金
山东省自然科学基金(ZR2014EEM010)
亚稳材料制备技术与科学国家重点实验室(燕山大学)开放课题(201507)
关键词
铁素体基球墨铸铁
硅固溶强化
显微组织
断口形貌
力学性能
ductile cast iron with ferritic-matrix
solution strengthening
microstructure
fracture morphology
mechanical properties
