内压对镁合金差温内压成形起皱行为的影响  

Effect of internal pressure on wrinkling behavior of magnesium alloy tube in warm hydroforming with non-uniform temperature field

作　　者：张文达[1] 刘钢[1] 魏文庭[1] 

机构地区：[1]哈尔滨工业大学金属精密热加工国家级重点实验室,哈尔滨150001

出　　处：《材料科学与工艺》2013年第4期71-75,共5页Materials Science and Technology

基　　金：国家自然科学基金资助项目(51075100)

摘　　要：针对镁合金管材热态内压成形存在的壁厚不均、膨胀率小等问题,本文提出利用温度差控制变形的差温内压成形新方法,沿管材轴向建立了具有不同温度梯度的温度场,开展非均匀温度场作用下的镁合金管材塑性失稳起皱行为研究,研究了内压对镁合金差温内压成形起皱参数的影响规律。当恒定内压8MPa时,成形后形成均匀的三个皱纹;采用线性增加的内压补料,成形后仅形成均匀的两个皱纹。恒定内压下轴向补料有助于形成更均匀的多点起皱,变内压轴向补料会改变起皱临界条件,提高了成形区材料的稳定性,抑制后续皱纹的形成。Tube warm hydroforming of Mg alloy tube usually induces poor thickness uniformity and low expan- sion ratio, therefore, a new warm hydroforming process with non-uniform temperature field is presented. The temperature field along the tube axis with different temperature gradient is established to control the plastic de- formation behavior of the tube blank. The plastic wrinkling tests of Mg alloy tubes with non-uniform tempera- ture field are carried out, and the effect of internal pressure on wrinkling behavior of magnesium alloy tube in warm hydroforming with non -uniform temperature field is studied. The results show that three uniform wrin- kles can be formed when the internal pressure is kept as a constant, and only two uniform wrinkles can be formed using linearly increasing internal pressure. Axial feeding with constant internal pressure contributes to the formation of uniform multi - point wrinkling, but the axial feeding with linearly increasing internal pressure can change the critical conditions of wrinkling, which improve the stability of forming zone and inhibit the for- mation of subsequent wrinkles.

关 键 词：镁合金 内压 热态内压成形 差温 起皱行为 

分 类 号：V524.3[航空宇航科学与技术—人机与环境工程]