Microstructure and mechanical properties of complex-shaped 7075 aluminium alloy prepared using modified polyoxymethylene-based feedstock  

改性聚甲醛基喂料制备复杂形状7075铝合金的显微组织和力学性能

作　　者：Heng ZOU Meng-xiong CHEN Yang FU Hui-wen XIONG Lei ZHANG Ke-chao ZHOU 邹恒;陈梦熊;付杨;熊慧文;张雷;周科朝(中南大学粉末冶金国家重点实验室,长沙410083)

机构地区：[1]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第12期3862-3875,共14页中国有色金属学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(No.2021YFB3701900)。

摘　　要：Additives of dioctyl phthalate(DOP),ethylene bis-stearomide(EBS),and epoxy(EP)were selected to modify the surface of 7075 Al alloy powder.Functional groups in DOP and EBS form hydrogen bonds with hydroxyl groups on the surface of Al powder.Additionally,the epoxy groups in the epoxy resin undergo ring-opening reactions with hydroxyl groups.The above interactions increased the compatibility between alloy powder and polyoxymethylene(POM).After sintering,samples containing DOP and EP presented high contents of C and O,while the part with EBS additive exhibited the lowest contents of 0.006 wt.%C and 0.604 wt.%O,respectively.Excessive C tends to accumulate at grain boundaries during sintering.Concurrently,excessive O causes secondary oxidation of aluminium alloy powder,inhibiting the sintering densification process.Therefore,the densities of the samples containing DOP and EP were only 85.52%and 79.01%,respectively.In contrast,using EBS as an additive,high-quality aluminium alloy parts were achieved,with a relative density of 97.64%and a tensile strength of 193 MPa.以邻苯二甲酸二辛酯(DOP)、乙撑双硬脂酰胺(EBS)和环氧树脂(EP)为添加剂修饰7075 Al合金粉末表面。DOP和EBS中的官能团与Al粉末表面的羟基形成氢键。此外,环氧树脂中的环氧基团与羟基发生开环反应。上述相互作用增加了合金粉末与聚甲醛(POM)之间的相容性。烧结后,含DOP和EP的样品中C、O含量较高,而含EBS添加剂的样品具有最低的C、O含量,分别为0.006%C(质量分数)和0.604%O(质量分数)。在烧结过程中,过量的C倾向于积聚在晶界处。同时,过量的O会导致铝合金粉末的二次氧化,从而抑制烧结致密化过程。因此,含有DOP和EP的样品致密度分别仅为85.52%和79.01%。相比之下,以EBS作为添加剂时可获得相对密度为97.64%、抗拉强度为193 MPa的高质量铝合金零件。

关 键 词：7075 aluminium alloy polyoxymethylene-based feedstock additives compression moulding metal injection moulding microstructure mechanical properties 

分 类 号：TG146.21[一般工业技术—材料科学与工程]