加钛方式及钛含量对A356合金的低周疲劳性能的影响

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。

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

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.