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利用三维有限元模型研究工业纯钛室温等径弯曲通道挤压(ECAP)变形过程,通过数值模拟分析模具通道夹角、外圆角及摩擦条件等参数对材料变形区的应变分布及挤压载荷的影响规律,获得了在室温下对工业纯钛进行ECAP变形的最优工艺参数。模拟结果表明:三维模型考虑了模具接触及摩擦的影响,比二维平面模型更客观、准确地反映了试样的应变分布状况。Φ=120°,Ψ=20°的模具参数为最优,试样可在较低的挤压载荷获得较大的塑性变形,增加通道背部摩擦可扩大试样主变形区体积,改善变形均匀程度。最终采用两通道夹角Φ=120°,外圆角Ψ=20°的模具,在背部不润滑的摩擦条件下成功实现了工业纯钛室温等径弯曲通道单道次变形。
The three-dimensional finite element model was used to study the deformation process of ECOP of commercial pure titanium at room temperature. The strain distribution and the compressive load on deformation zone of the material were analyzed by numerical simulation of the included angle, The optimal process parameters of ECAP deformation of commercial pure titanium at room temperature were obtained. The simulation results show that the three-dimensional model considers the influence of the contact and the friction of the mold and reflects the strain distribution of the specimen more objectively and accurately than the two-dimensional planar model. The parameters of Φ = 120 ° and Ψ = 20 ° are the best, and the specimen can get larger plastic deformation under the lower extrusion load. Increasing the friction in the back of the channel enlarges the volume of the main deformation zone and improves the uniform deformation . In the end, a two-pass mold with Φ = 120 ° included angle and ψ = 20 ° external angle was used to successfully achieve the single pass deformation of the commercial pure titanium at room temperature under the condition of non-lubricated friction.