摘要 Al-Si系铸造合金是典型的铸造铝合金活塞材料。为研究材料成分及热处理工艺对活塞合金力学性能及热膨胀系数的影响,文中针对Al-Si-Cu-Mg-Ni多元新型活塞合金,通过改变Cu、Ni含量及热处理方式,采用X射线衍射分析、金相观察、扫描电镜分析、透射电镜分析等表征手段,研究了合金成分变化以及长时间稳定化处理对合金微观结构组织、力学性能和热膨胀系数的影响规律。研究结果表明:经过500℃/50 h稳定化处理后,由于基体中弥散出大量的θ相,两种不同成分合金的抗拉强度相比铸态均有一定提高,分别提高了12%和15%;长时间稳定化处理可以降低合金热膨胀系数,并使合金的热膨胀系数更稳定,在经过500℃/50 h的稳定化处理后,两种合金相比铸态下的热膨胀系数分别降低了6.4%和10.6%,稳定的θ相析出可能是改变热膨胀系数的原因之一;Cu、Ni含量提高,热稳定性更好的γ-Al7-Cu4Ni相变多,进一步使热膨胀系数降低。 Al-Si cast alloy is a typical material for making aluminum alloy pistons.To study the effect of composition and heat treatment on mechanical properties and thermal expansion coefficient of piston alloy,the paper investigates the effects of different composition and long term stabilization on the microstructure,mechanical properties and thermal expansion coefficient of Al-Si-Cu-Mg-Ni multi element piston alloy by means of X ray diffraction analysis,metallographic observation,scanning electron microscope analysis and transmission electron microscope analysis.The results show that after 500℃/50 h stabilization treatment,the tensile strength of the two alloys with different components is increased by 12%and 15%respectively compared with the as cast state alloy,and that the thermal expansion coefficient of the alloy is more stable after 500/50 h stabilization treatment.The thermal expansion coefficients of the two alloys are reduced by 6.4%and 10.4%,respectively,compared with that of the as cast state.The stableθphase precipitation may be one of the reasons for the change of the thermal expansion coefficient.With the increase of Cu and Ni content,γAl7-Cu4-Ni with better thermal stability has more phase transition,which reduces further the thermal expansion coefficient.
出处 《西安工业大学学报》 CAS 2021年第1期67-73,共7页 Journal of Xi’an Technological University
基金 陕西省创新人才推进计划科技创新团队(2017KCT 05) 陕西省重点研发计划项目(2019ZDLGY0509) 陕西省教育厅服务地方专项计划项目(19JC022)。
关键词 Al-Si-Cu-Mg-Ni合金 稳定化处理 热膨胀系数 微观组织 Al-Si-Cu-Mg-Ni alloy tabilization treatment thermal expansion coefficient microstructure
