| Aluminum’s light weight,safety,availability and ability to achieve high energy density storage through three-electron transfer make it an ideal choice for metal-air battery systems with great potential for future development.However,the polarization and hydrogen evolution corrosion of aluminum anode restrict its commercial application.As the anode of Al-air battery,6061 aluminum alloy shows relatively good discharge performance,but there is serious hydrogen evolution corrosion in strong alkali electrolyte.Therefore,this paper firstly prepared an electrolyte that could inhibit the hydrogen evolution corrosion rate of aluminum anode and improve the discharge performance.Then,Ce O2,which has the ability to purify melt and improve the matrix microstructure,was used as the strengthening phase to prepare Ce O2/6061 aluminum matrix composites by SLM technology.In view of the forming quality,electrochemical performance and discharge performance of the materials in the electrolyte,The SLM forming process was studied,and the process parameters were optimized and the error analysis was carried out based on response surface test and genetic algorithm.The main research contents and conclusions are as follows:（1）Electrolyte optimization research for improving discharge performance of aluminum anode:The influence of sodium polyacrylate（PAAS）/zinc oxide（Zn O）composite corrosion inhibitor on electrochemical performance and discharge performance of aluminum anode was investigated.By comparing the surface morphology and corrosion product composition of aluminum anode after discharge,the corrosion inhibition mechanism of corrosion inhibitor was clarified.The results show that PAAS+Zn O composite corrosion inhibitor can significantly inhibit the self-corrosion of 6061 aluminum alloy in alkaline electrolyte.When the discharge current density is 10 m A/cm2,the discharge voltage increases from-1.294 V to-1.402 V.Zn O is a phase corrosion inhibitor,which inhibits anode self-corrosion by forming zinc salt deposit layer on the surface of aluminum anode,while PAAS is an adsorption corrosion inhibitor,whose electrostatic adsorption makes the zinc salt deposit more compact and stable.The synergistic action of composite corrosion inhibitors can significantly improve the electrochemical performance of aluminum anode in electrolyte.Therefore,the discharge of the SLM-formed Ce O2/6061 aluminum matrix composites is carried out in the Na OH+PAAS+Zn O electrolyte selected in this section to improve the comprehensive discharge performance.（2）Effect of Ce O2 content on microstructure and properties of Aluminum matrix composites formed by SLM:By adding different mass fractions of Ce O2 into aluminum alloy powder,the composite powder was fully mixed by ball milling technology,and the Ce O2/6061 aluminum matrix composite was formed by SLM technology.The effects of Ce O2addition amount on microstructure,surface forming quality,electrochemical and discharge properties of Ce O2/6061 composite were investigated.The results show that under the action of high energy laser,Ce O2 can react in situ with aluminum matrix to form Al-Ce compound Al3Ce phase,which can act as heterogeneous nucleation point,improve nucleation rate,hinder grain growth,promote grain refinement,and reduce the generation of thermal cracks.The grain size of the 6061 sample without Ce O2 is 75.3 nm,and the grain size of the 1.0 wt.%Ce O2/6061 Al matrix composite is the smallest（47.0 nm）.When Ce O2 content is 1.0 wt.%,the forming quality and properties of Ce O2/6061 Al matrix composites are the best.Compared with pure 6061 material,the corrosion rate of 1.0 wt.%Ce O2/6061 aluminum matrix composite decreases from 6.107×10-4 g·cm-2·min-1 to 2.525×10-4 g·cm-2·min-1.The polarization resistance R1 increases from 2.286×10-1Ω·cm2 to 5.780×10-1Ω·cm2.When the discharge current density is 10 m A/cm2,the discharge voltage reaches-1.561 V,and the anode utilization rate is 64.6%.（3）Effect of laser process parameters on properties of Ce O2/6061 composites:Combined with surface morphology,self-corrosion,electrochemical performance and discharge performance tests,the effects of laser power,scanning speed and scanning distance on the forming quality and discharge performance of 1.0 wt.%Ce O2/6061 composite were studied.It was found that when the laser power was 280 W,scanning speed was 1000 mm/s and scanning distance was 0.13 mm.Forming quality is directly related to whether aluminum anode can dissolve uniformly in discharge solution,and the dissolution state of the anode layer shedding is conducive to improving the anode utilization rate and discharge voltage.The optimal process parameters are:the laser power is 260-300 W,the scanning speed is 900-1100mm/s,and the scanning interval is 0.11-0.15 mm.（4）Study on multi-objective process optimization of forming quality of Ce O2/6061composites:The response surface test was designed based on Box-Behnken principle,and the formability prediction model of the composite was established according to the process parameters,and the variance analysis and significance test were carried out.The corrosion potential,self-corrosion rate and discharge voltage were taken as the optimization objectives.The optimal combination of process parameters of SLM forming Ce O2/6061 composite was obtained by genetic algorithm.The optimal forming quality and properties of the composites are as follows:laser power 265-285W,scanning speed 985-1025 mm/s,scanning spacing0.116-0.140 mm.The optimization process parameters were selected to carry out reliability experiments,and the errors were all within 3.0%,which verified the accuracy and reliability of the model. |
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