CAJ | 학술논문

采用粉末冶金技术制备块体超细晶Mg-3A1-Zn合金.首先采用球磨Mg、Al、Zn混合粉末来制备纳米晶粉末,所得的粉末的平均晶粒尺寸为45 nm.随后将球磨好的粉末封入铝包套内,分别在室温和633 K温度下,在真空烧结炉内进行真空热压.然后将烧结后的样品在423 K下挤压以进行进一步的致密化处理.结果表明:致密后的冷压样品的晶粒尺寸为180 nm,而热压坯的晶粒尺寸为600 nm,冷压样品的屈服强度达464 MPa;超细晶镁合金的强化机制主要是细晶强化,这主要是由于HCP结构的材料晶粒尺寸对材料的影响更为明显.固化后冷压样品的最终密度为(1.777±0.006) g/cm3,而热压样品的最终密度为(1.800±0.006) g/cm3.
채용분말야금기술제비괴체초세정Mg-3A1-Zn합금.수선채용구마Mg、Al、Zn혼합분말래제비납미정분말,소득적분말적평균정립척촌위45 nm.수후장구마호적분말봉입려포투내,분별재실온화633 K온도하,재진공소결로내진행진공열압.연후장소결후적양품재423 K하제압이진행진일보적치밀화처리.결과표명:치밀후적냉압양품적정립척촌위180 nm,이열압배적정립척촌위600 nm,냉압양품적굴복강도체464 MPa;초세정미합금적강화궤제주요시세정강화,저주요시유우HCP결구적재료정립척촌대재료적영향경위명현.고화후냉압양품적최종밀도위(1.777±0.006) g/cm3,이열압양품적최종밀도위(1.800±0.006) g/cm3.
Powder metallurgy was used to fabricate a bulk ultrafine grain size (UFG) Mg-3Al-Zn alloys.Nanocrystalline alloy powders with an average grain size of 45 nm were synthesized via ball milling of elemental powders of Mg,Al and Zn.The milled powders canned in Al containers were subjected to cold (at room temperature) or hot press (for 40 min at 633K),respectively,in a vacuum furnace.The sintered samples were extruded at 423 K to further solidify.The results show that the average grain size is 180 nm for the cold samples,and that is 600 nm for the hot samples.The cold-press alloys show a yield stress of 426 MPa.The high strength of UFG Mg is attributed to the fine grain strengthening mechanism resulting from the strong dependence of strength on the grain size for HCP metals.The consolidated samples of the cold-press and hot-press alloys have a final density of (1.777±0.006) and (1.800±0.006) g/cm3,respectively.