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在25—704℃下,研究了工厂退火的、双重退火的和交叉轧制的Ti—6Al—4V厚板的平面塑性各向异性参数和法向塑性各向异性参数(分别为△R与R)与温度的关系。这两个参数与合金的织构和显微组织有关,并以最大负荷下拉伸试样的塑性应变比(R),即其宽度应变对厚度应变的比值来表征,最大负荷约相当于0.065纵向应变,试样取向与轧向成0°、45°和90°。随着温度的升高,具有α变形型基面织构的厚板的各向异性变化比具有β转变型织构厚板的各向异性变化要大。此种性质与织构的漫散程度有关,也与主要塑性变形方式由孪晶转变成滑移的热诱致转变有关。由于存在织构,上述结果有力表明:控制加工温度可能有利于改变Ti—6Al—4V厚板的塑性各向异性,以满足给定加工工序对其成形性的要求。
Plane plastic anisotropy parameters and normal plastic anisotropy parameters (ΔR and R respectively) of factory-annealed, double-annealed and cross-rolled Ti-6Al-4V slabs were studied at 25-704 ℃ ) And temperature. These two parameters are related to the texture and microstructure of the alloy and are characterized by the plastic strain ratio (R) of the tensile specimen at maximum load, ie, the ratio of its width strain to its thickness strain, with a maximum load of approximately 0.065 Longitudinal strain, sample orientation and rolling into 0 °, 45 ° and 90 °. As the temperature increases, the anisotropy of the plank with α-deformed base texture changes more than the anisotropy with β-transform textured slab. This property is related to the degree of dispersion of the texture and also to the thermal-induced transformation of the main plastic deformation mode from twin to slip. Due to the texture, the above results strongly suggest that controlling the processing temperature may be beneficial for changing the plastic anisotropy of Ti-6Al-4V slabs to meet the formability requirements of a given processing operation.