论文部分内容阅读
钛合金在航空、航天等工业中有广泛的应用,其中TC1钛合金在变形温度为860℃,应变速率为7.5×10-4 s-1时,延伸率最大可达710%,具有良好的超塑性,通过超塑性气压成形工艺可成形形状较为复杂的零件。根据深型腔负角度钛合金法兰盘零件的特点,提出了超塑性气压成形工艺,并根据零件尺寸特征设计了弧形底面和平底两种的模具,同时,根据TC1拉伸力学特性建立了材料的高温本构关系,应用MARC有限元对其超塑成形过程进行了模拟。结果表明,弧形底面模具成形零件最薄处为1.2 mm,壁厚分布标准差为0.198 mm,变薄率为40%,在成形过程中最大应力约6.6 MPa;而平底模具成形的零件最薄处仅为0.82 mm,壁厚分布标准差为0.303 mm,变薄率高达59%,在成形过程中最大应力约7.8 MPa。因此弧形底面模具厚度分布较均匀,壁厚减薄较小,最大应力较小,降低了应力集中程度,是该类零件超塑成形工艺较为理想的模具。
Titanium alloy has a wide range of applications in aviation, aerospace and other industries. The TC1 titanium alloy has a maximum elongation of 710% at a deformation temperature of 860 ℃ and a strain rate of 7.5 × 10-4 s-1, Plasticity, the shape of the more complex parts can be formed by the superplastic pressure forming process. According to the characteristics of deep cavity negative angle titanium alloy flange parts, a superplastic pressure forming process was proposed. According to the characteristics of the part size, two kinds of molds, arc bottom and flat bottom, were designed. At the same time, according to the tensile mechanics characteristics of TC1 Material constitutive relationship of high temperature, the application of MARC finite element simulation of its superplastic forming process. The results show that the thinnest part of the curved bottom mold is 1.2 mm, the standard deviation of the wall thickness distribution is 0.198 mm, the thinning rate is 40% and the maximum stress is about 6.6 MPa during the forming process. The thinnest part of the flat- Only 0.82 mm, the standard deviation of wall thickness distribution is 0.303 mm, the thinning rate is as high as 59%, and the maximum stress during forming is about 7.8 MPa. Therefore, the arc bottom mold thickness distribution is more uniform, smaller wall thickness thinning, the maximum stress is smaller, reducing the stress concentration, is the type of parts superplastic forming process is an ideal mold.