【摘要】：泡沫鋁芯夾層板由泡沫鋁芯和金屬面板組成,具有低密度、高阻尼、高比強度、高吸能以及電磁屏蔽等性能,并在很大程度上解決了單一泡沫鋁強度低的缺點。鑒于目前泡沫鋁芯夾層板存在泡沫鋁芯與表面層界面連接不夠理想,力學性能受表面層與泡沫芯結(jié)合方式制約等問題,本文提出了一種新型的近凈成型制備泡沫鋁芯夾層板的方法——真空發(fā)泡法,并對真空發(fā)泡法制備泡沫鋁芯夾層板進行了研究,主要研究結(jié)果如下：(1)以Al-Si12-Ca3合金為原料,采用真空發(fā)泡法成功制備出厚度20-35mm的泡沫鋁芯夾層板,夾層板表面層厚度0.5-1mm,內(nèi)部孔結(jié)構(gòu)均勻,孔徑2.5-7mm,孔隙率75-85%,表面層與泡沫鋁芯為冶金結(jié)合。(2)制備了含有初始氣孔的可真空發(fā)泡熔體,獲得的最佳初始氣孔制備工藝參數(shù)為：TiH2添加量0.3%,熔體溫度630℃,發(fā)泡劑分散攪拌速度2000r/min,分散攪拌時間120s。將可真空發(fā)泡熔體在真空作用下充型制備泡沫鋁芯夾層板,其最佳真空發(fā)泡工藝為：真空度10Pa,真空發(fā)泡時間30s。(3)對真空發(fā)泡法制備的泡沫鋁芯夾層板進行拉伸性能和三點彎曲性能測試,結(jié)果表明：孔隙率對泡沫鋁芯夾層板力學性能影響較大,孔隙率從75%增大到85%,抗拉強度從18.89MPa降低到10.73MPa,抗彎強度從16.20MPa降低到8.73MPa。與相同孔結(jié)構(gòu)的泡沫鋁芯相比,泡沫鋁芯夾層板相比泡沫鋁芯抗拉強度提高了24.57%,抗彎強度提高了13.67%。(4)初始氣孔氣泡形核以非均勻形核為主,形核速率與H2分子濃度和形核質(zhì)點數(shù)成正比。真空作用下,熔體氣泡內(nèi)部氣壓與真空罐內(nèi)氣壓形成的壓力差是氣泡膨脹的動力,真空罐內(nèi)氣壓釋放越快,氣泡膨脹越快。整個氣泡膨脹過程中,氣泡膨脹速率先慢后快。(5)泡沫熔體的外層胞壁在真空膨脹作用及模具作用下,相鄰胞壁互相擠壓使其多邊形化和平整化,熔體首先在模具表面結(jié)殼凝固形成表面層,自然冷卻得到泡沫鋁芯夾層板。
[Abstract]:The foam aluminum core sandwich plate is composed of foam aluminum core and metal panel, which has the properties of low density, high damping, high specific strength, high energy absorption and electromagnetic shielding, and solves the disadvantage of low strength of single aluminum foam to a great extent. In view of the fact that the interface connection between the foam aluminum core and the surface layer is not ideal, and the mechanical properties of the foam aluminum core sandwich plate are restricted by the combination mode of the surface layer and the foam core, and so on, In this paper, a new method of preparing foam aluminum core sandwich plate by near net molding, vacuum foaming method, is proposed, and the preparation of foam aluminum core sandwich plate by vacuum foaming method is studied. The main results are as follows: (1) the foam aluminum sandwich plate with thickness 20-35mm was successfully prepared by vacuum foaming method with Al-Si12-Ca3 alloy as raw material. The surface layer of the sandwich plate is 0.5 mm thick and the internal pore structure is uniform. The pore size is 2.5 脳 7 mm, the porosity is 75 鈮，

本文編號：2494971