加钛方式及钛含量对A356合金的低周疲劳性能的影响

Effects of Titanium Alloying Methods and Titanium Content on the Low Cycle Fatigue Behavior of A356 Alloys

研究了不同加钛方式和钛含量对A356合金低周疲劳性能的影响,结果表明A356合金的循环硬化行为对合金的加钛方式和钛含量敏感。钛含量为0.14%的合金总是比钛含量为0.10%的合金具有更高的循环硬化率。在低应变时两种加钛方式的循环硬化行为类似,在高应变时电解加钛合金表现为类似“饱和”的准稳定形变状态,而熔配加钛合金表现为持续的循环硬化行为。疲劳寿命仅对含钛量敏感,钛含量为0.10%时合金的低周疲劳寿命要优于钛含量为0.14%的合金。但是加钛方式对疲劳寿命的影响很小,如果钛含量相近,则两种加钛方式合金的低周疲劳寿命差别不大。

The effects of Ti alloying method and Ti content on the low cycle fatigue behaviors of A356 alloy were investigated.The results show that cycle-hardening behavior of A356 alloy was susceptive to both the Ti alloying method and Ti content,in which the alloy with (0.14%) Ti always has higher cyclic hardening rate than that of the alloys with 0.1% Ti.Both A356 alloy alloyed by electrolysis (EA356 alloys) and by melting Al-10Ti master alloys (MA356 alloys) exhibit the similar cyclic hardening behavior when tested at low strain amplitude,while tested at high strain amplitude,the EA356 alloys show the quasi-stable state that cyclic hardening ability approaches to saturation,and for the MA356 alloys,the cyclic hardening continuously proceeds.The low-cycle fatigue life of the alloy is only sensitive to the Ti content.Whether alloyed by electrolytic low-Ti alloys or Al-Ti master alloy,the alloy with 0.1% Ti always has higher low-cycle fatigue life than that of the alloy with 0.14% Ti.The EA356 alloys have the similar low-cycle fatigue life as the MA 356 alloys if two kinds of alloys have the same Ti content.