泡沫铝复合结构制备工艺及力学性能研究

发布时间：2018-05-26 18:33

  本文选题：APM + 胶粘复合　； 参考：《太原科技大学》2017年硕士论文

【摘要】：将多孔泡沫金属芯材与致密外壳通过一定连接方式组合成复合结构,既具有泡沫芯材的轻质、耐冲击、抗振阻尼等特点,亦具有致密外壳的高强度特点,从而使泡沫金属在民生、国防、航空航天等领域具有广阔的应用前景。目前泡沫铝复合结构的制备方式众多,但多数制备工艺过程复杂,模具成本较高,尤其对于一些大型复杂构件,现有复合工艺难以保证充型效果及芯材孔隙率的均匀性。本文基于传统粉末冶金发泡法(Powder Compacted Foaming,简称PCF法)泡沫铝制备工艺,提出一种新型复合工艺。即通过泡沫化过程制备出具有先进孔隙结(Advanced Pore Morphology,简称APM)的泡沫铝硅合金填料小球,随后利用环氧涂覆胶粘和环氧发泡胶粘两种方法将小球填充到中空模具中,形成夹芯复合结构。通过实验获得复合结构制备工艺的基本参数,并对其发泡和粘结机理进行分析。对利用此法获得的复合结构进行力学性能测试,并与中空模具的力学性能进行比较。具体结论如下:(1)小球制作过程:利用PCM法制备泡沫铝小球。发泡温度、加热速度、发泡剂种类对试样膨胀过程和孔结构参数有较大的影响。当加热速度为2.6℃/s时小球发泡综合效果最好;发泡时间接近最大膨胀点时间点时孔结构最为均匀,APM小球外形球形度也较高;以Zr H2为发泡剂的预制体在膨胀过程中的温度平台区长度、到达最大膨胀点的温度均要高于以Ti H2为发泡剂的预制体。(2)粘接复合过程:采用环氧胶粘和环氧发泡两种方法用APM小球填充薄壁钢管。采用环氧胶粘工艺进行粘接充型时,小球仍保持原位填充状态,填充均匀性仅与初始填充率有关;而采用环氧发泡工艺进行粘接充型时,直径为15mm的小球经环氧树脂发泡之后的分散均匀性强于直径为20mm的小球;而当APM小球初始填充率在80%和100%时,发泡后在管中的分散均匀性要强于初始填充率为50%与30%的管件。采用直径为15mm APM小球,填充率为80%和100%两种参数对异形件进行充填效果分析,发现采用直径15mm APM小球、当APM填充率100%时效果最好;且APM填充法提高了异形件内部泡沫体孔的平均圆形度,增强了孔结构的均匀性和重现性。(3)力学性能研究:采用环氧胶粘和环氧发泡两种方法制备两组复合管件样本,将APM小球、薄壁空管及复合管件分别进行准静态压缩,结果表明:APM小球变形过程中为首先靠近工作台两端部位孔穴最先变形坍塌,随后向中心部位扩展,直至全部压溃;APM单元小球的应力-载荷曲线与传统泡沫铝形状大致相同,平台区跨度较大。而薄壁钢管主要表现为非对称变形模式,环氧胶粘-APM填充管为混合模式,环氧发泡-APM填充管表现出较典型的六角变形模式,且后二者褶皱数目要多于薄壁空管。环氧胶粘-APM复合管与环氧发泡-APM复合管提高了压缩载荷水平,环氧发泡-APM复合管的理想吸能效率约为薄壁空管的188%,可达环氧胶粘-APM复合管的113%。
[Abstract]:The porous foam metal core and the dense shell are combined to form a composite structure by a certain connection, which has the characteristics of light weight, shock resistance, vibration resistance and damping of the foam core, and also has the characteristics of high strength of the dense shell. Thus, foam metal has a broad application prospect in the fields of people's livelihood, national defense, aerospace and so on. At present, there are many preparation methods of aluminum foam composite structure, but most of the preparation process is complex and the die cost is high. Especially for some large and complex components, the existing composite process is difficult to ensure the filling effect and the uniformity of core porosity. Based on the traditional powder metallurgical foaming method powder Compacted foaming (PCF) foam aluminum preparation process, a new composite process is proposed in this paper. That is to say, the foamed Al-Si alloy filler pellets with advanced pore junctions, Advanced Pore Morphology (APM) were prepared through the foaming process, and then the spheres were filled into the hollow mold by using epoxy coating adhesive and epoxy foaming adhesive. A sandwich core composite structure is formed. The basic parameters of the preparation process of composite structure were obtained by experiments, and the foaming and bonding mechanism were analyzed. The mechanical properties of the composite structure obtained by this method were tested and compared with the mechanical properties of the hollow die. The main conclusions are as follows: PCM method is used to prepare foamed aluminum pellets. Foaming temperature, heating speed and type of foaming agent have great influence on the expansion process and pore structure parameters. When the heating speed is 2.6 鈩，

本文编号：1938433