附加水冷对电弧增材制造4047铝合金构件组织与力学性能的影响

Effect of the additional water-cooling on the microstructure and mechanical properties of wire arc additive manufacturing of 4047 aluminum alloy

为解决电弧连续增材时,由于热积累效应导致堆敷层的塌陷问题,在基板底部加装水冷铝板,制备了水冷断续、水冷连续两种不同工艺的4047铝合金直壁构件,并制备无水冷条件下的增材构件作为对照.通过对比3种工艺条件下的构件基板热循环曲线、晶粒形貌、抗拉强度、硬度和断后伸长率,研究水冷条件对增材构件宏观形貌、微观组织和力学性能的影响.结果表明,水冷断续条件能够有效降低热量积累,增材构件侧壁更加平整.水冷连续条件下增材直壁构件成形最好,两端无塌陷产生,且成形效率最高.3种增材构件底部晶粒都以等轴晶为主,其余部位都以柱状晶和树枝晶为主.水冷连续条件下构件的晶粒尺寸最大,水冷断续条件下晶粒尺寸最小.各增材工艺制备的构件力学性能与ZL102铸造铝合金相当,其中水冷断续工艺制备的增材构件力学性最好.创新点:(1)通过加装水冷铝板增强散热,解决了电弧连续增材4047铝合金时堆敷层塌陷问题,改善了增材构件成形质量.(2)在水冷条件下采用连续增材制造工艺,增材构件既满足了基本性能要求,又提高了成形效率.

In order to solve the problem of deposited metal collapse caused by heat accumulation effect during the continuous process of wire arc additive manufacturing,a water-cooling aluminum plate was applied to the bottom of the substrate,and 4047 aluminum alloy straight wall components were prepared under two processes:intermittent forming with watercooling,and continuous forming with water-cooling.A component was also additived without water-cooling for benchmark specimen.By comparing the thermal cycle curve,grain morphology,tensile strength,hardness and elongation,the effect of water-cooling conditions on the macroscopic morphology,microstructure and mechanical properties of the additive components were analyzed.The results showed that heat accumulation was effctively reduced by water-cooling,and flatter component side walls were obtained.The straight wall additive component exhibited the best performance under the continuous forming with water-cooling,showing no collapses at either end,and the forming efficiency was also high.The grains at the bottom of the components are mainly equiaxed crystals,and columnar and dendritic crystals at other sites.The grain size of the component is the largest under continuous forming with water-cooling and the smallest under intermittent forming with water-cooling.The mechanical properties of all components are similiar to that of ZL102 casting aluminium alloy.The component prepared by the intermittent forming with water-cooling exhibited the best mechanical properties.Highlights:(1)By applying water-cooling aluminum plate to promote heat dissipation,the problem of coating collapses during continuous arc addictive manufacturing of 4047 aluminum alloy was solved,and the forming quality of the additive component was improved.(2)Continouous wire arc additive manufacturing under watercooling conditons has not only produced components with satisfactory performance but also improved the forming efficiency.