(郑州大学 物理工程学院，材料物理教育部重点实验室，郑州 450052)
摘 要: 采用电解低钛铝合金、 工业纯铝与Al-10Ti中间合金， 制备了具有不同钛含量的电解加钛A356合金（EA356 合金）和熔配加钛A356合金（MA356合金）， 研究了加钛方式和钛含量对A356合金的应变能密度和低周疲劳性能的影响。 结果表明： 4种合金均表现为明显的循环硬化行为；具有较高钛含量的E14、 M14合金的循环硬化能力高于低钛含量的E10和M10合金； 合金的塑性应变能密度受应变幅的影响且具有循环相关性；高应变幅时， 塑性应变能较高但随循环周次变化较小； 当应变幅较低时， 合金的塑性应变能较小但变化较大， 特别是塑性较好的E10和M10合金； 无论是电解加钛还是熔配加钛， 钛含量为0.1%的E10和M10合金的的塑性应变能密度和疲劳寿命均优于钛含量为0.14%的E14和M14合金；合金的疲劳寿命对加钛方式不敏感， 在相同钛含量下， 两种加钛方式的合金具有相近的低周疲劳寿命。
关键字: A356合金； 循环硬化； 塑性应变能密度； 疲劳寿命
plastic strain energy of A356 alloys
（ School of Physics Engineering, Key Laboratory of Material Physics，
Ministry of Education, Zhengzhou University, Zhengzhou 450052, China）
Abstract: Two kinds of EA356 alloys(adding titanium by electrolysis method) and MA356 alloys(adding titanium by melting Al-Ti master alloys), are produced by electrolytic low-titanium aluminum alloys, pure aluminum and Al-10%Ti master alloys respectively. The effects of titanium alloying method and titanium content on the plastic strain energy density and low-cycle fatigue behavior of A356 alloys were investigated. The results show that four kinds of A356 alloys show cycle hardening behavior. The cyclic hardening ability of alloys with high titanium content such as E14 and M14 alloys is higher than that of alloys with low titanium content such as E10 and M10 alloys. The values of plastic strain energy density are affected by the plastic strain amplitude and change with the cycle numbers. The values of plastic strain energy density are higher at high strain amplitude and the change with cycle number is less. But at low strain amplitude, its values are less and the change with cycle number is acute, especially for the alloys with low titanium content and low yield strength such as E10 and M10 alloys. Whether the EA356 alloys or MA356 alloys, the alloys with 0.1%Ti have higher plastic strain energy density and low cycle fatigue life compared with that of alloys with 0.14% Ti. The fatigue life is insensitive to the titanium alloying method. If alloys have the same titanium content, two kinds of alloys have similar low cycle fatigue life.
Key words: A356 alloys; cyclic hardening; plastic strain energy density; fatigue life
