基于薄壁環(huán)壓縮的鋁合金管材應(yīng)力-應(yīng)變行為

基于薄壁環(huán)壓縮的鋁合金管材應(yīng)力-應(yīng)變行為Stress-strain behavior of aluminum alloy pipe based on thin-walled ring compression

采用環(huán)壓縮實驗研究LF2M鋁合金薄壁管材在應(yīng)變速率為0.1~1 s-1，成形溫度為350~475 ℃條件下的應(yīng)力-應(yīng)變行為。提出一種薄壁環(huán)壓縮的方法，得到薄壁管材熱壓下的變形行為。結(jié)果表明：環(huán)壓縮試樣的高度選擇需要避免壓縮過程中出現(xiàn)起皺缺陷。試樣高厚比為1時，隨著壓縮量增加，切向壓應(yīng)力超過臨界值引起起皺失穩(wěn)；試樣高厚比為3時，隨著壓縮量增加，壓應(yīng)力超過臨界值，出現(xiàn)起皺現(xiàn)象；試樣的高厚比為2時，壓縮后試樣無起皺缺陷。因此，壁厚為1 mm時，環(huán)壓縮試樣的最佳高度為2 mm。LF2M鋁合金薄壁管材熱變形過程中的流變應(yīng)力可用雙曲正弦本構(gòu)關(guān)系來描述，平均激活能為160.67 kJ/mol。

The stress-strain behavior of LF2M aluminum alloy of thin-walled tube during hot compressing deformation was studied, under the conditions of strain rate range of 0.1-1 s-1, and the temperature range of 350-475 ℃. A method of thin-walled ring compression was proposed to obtain the deformation behavior of the thin-walled tube under hot extrusion. The results show that the height of the ring compression sample is selected to avoid wrinkling defects during the compression process. When the ratio of the height to thickness is 1, with the increase of the amount of compression, the tangent pressure exceeds the critical value caused to the wrinkling destabilization. When the ratio of the height to thickness is 3, the compression stress exceeds the critical value caused to the wrinkling destabilization with the increase of the amount of compression. When the ratio of the height to thickness is 2, the specimen have no wrinkling destabilization. Therefore, when the wall thickness is 1mm, the optimum height of the ring compression specimen is 2 mm. The flow behavior of LF2M aluminum alloy of thin-walled tube is described by the hyperbolic sine constitutive equation, and an activation energy of 160.67 kJ/mol is calculated.

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