(重慶大學(xué) 材料科學(xué)與工程學(xué)院，機(jī)械傳動(dòng)國(guó)家重點(diǎn)實(shí)驗(yàn)室，重慶 40044)
摘 要: 通過(guò)活性鎢極氬弧焊接將石墨烯納米片溶入AZ31鎂合金中，制得石墨烯/AZ31鎂合金復(fù)合焊接接頭。研究石墨烯加入量對(duì)復(fù)合焊接接頭組織和性能的影響。結(jié)果表明：石墨烯納米片在Marangoni逆流的運(yùn)載和電磁力的攪拌作用下，均勻分布在AZ31鎂合金基體中。均勻分散的石墨烯納米片有效地細(xì)化鎂合金的晶粒組織，并顯著提高其接頭的力學(xué)性能。所有試樣中，4#石墨烯/AZ31鎂合金復(fù)合接頭的晶粒尺寸最小(約19.8 μm)，力學(xué)性能最優(yōu)，其極限拉伸強(qiáng)度和顯微硬度為198 MPa和68.9 HV，約為未添加石墨烯納米片AZ31鎂合金接頭的190.4%和130%，同時(shí)，接頭的韌性也達(dá)到最佳。因此，石墨烯納米片的添加量在1.41%左右時(shí)，能獲得性能最好的石墨烯/AZ31鎂合金復(fù)合接頭。
關(guān)鍵字: 石墨烯納米片；AZ31鎂合金；活性鎢極氬弧焊接；微觀組織；力學(xué)性能
（State Key Laboratory of Mechanical Transmission, College of Material Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:The graphene nanosheets/AZ31 magnesium alloy composite joints were fabricated by introducing graphene nanosheets into magnesium alloy through activating flux tungsten inert gas welding. The effects of graphene addition amount on microstructure and properties of composite joints were studied. The results show that graphene nanosheets evenly disperse in magnesium alloy matrix due to the combined effect of Marangoni convection and electromagnetic forces. The uniformly dispersed graphene nanosheets refine matrix crystals and enhance mechanical property of the composite joints. The minimum grain size (about 19.8 μm) and optimum of mechanical properties of sample 4# is obtained. The ultra-tensile strength and microhardness of the composite joints reach to 198 MPa and 68.9HV, about 190.4% and 130% of those of the joints without graphene nanosheets, respectively. Simultaneously, the toughness is also the best. Therefore, the grapheme nanosheets/AZ31 magnesium alloy composite joints with the best performance can be obtained when graphene addition amount is about 1.41%.
Key words: graphene nanaosheet; AZ31 magnesium alloy; activating flux tungsten inert gas welding; microstructure; mechanical property
