CAJ | 학술논문

在1100-H14铝合金基体表面开凹槽添加Ni粉进行搅拌摩擦加工(Friction Stir Processing,FSP),利用Ni粉在搅拌过程中的碎化及其与基体的原位反应生成的高强、高硬的金属间化合物制备强化的表面复合层.结果表明,不同于添加陶瓷颗粒的FSP工艺,Ni颗粒能在搅拌过程中充分碎化,并与铝基体原位合成金属间化合物,原位自生的增强体颗粒与基体是以金属键合的方式结合在一起,因此与基体金属间具有良好的界面相容性和界面结构,能够很大程度上改善颗粒的强化效果.增强颗粒与基体结合界面的性质对复合层硬度的影响非常显著,为了提高复合层硬度,提出了通过原位反应获得颗粒/基体的高强界面的模型.
재1100-H14려합금기체표면개요조첨가Ni분진행교반마찰가공(Friction Stir Processing,FSP),이용Ni분재교반과정중적쇄화급기여기체적원위반응생성적고강、고경적금속간화합물제비강화적표면복합층.결과표명,불동우첨가도자과립적FSP공예,Ni과립능재교반과정중충분쇄화,병여려기체원위합성금속간화합물,원위자생적증강체과립여기체시이금속건합적방식결합재일기,인차여기체금속간구유량호적계면상용성화계면결구,능구흔대정도상개선과립적강화효과.증강과립여기체결합계면적성질대복합층경도적영향비상현저,위료제고복합층경도,제출료통과원위반응획득과립/기체적고강계면적모형.
Friction stir processing (FSP) was conducted by using aluminum alloy plate 1100-H14. Prior to stiring, a rectangular groove was machined on the plate along the center of stir pass, in which nickel powder was filled. Via in-situ synthesis during the processing thermal cycle, Ni particles in Al base metal would react with Al to form hard particles of NiAl intermetallics. Thus, a composite layer would be fabricated. The results show that Ni particles were stir-crushed to pieces and NiAl_3 reactive particles, in submicron size, were formed. A portion of NiAl_3 particles were further refined by stir-crushing. The microhardness test shows evident increase of the hardness distributions in the composite layer. Compared with ceramic powders added in FSP, physical models were proposed to describe both particle-strengthing mechanisms. In-situ synthesesed intermetallic particles have the crystal boundaries to base metal with strong metallic bonds (twinned crystal boundary, for example), which makes difficulty for dislocatons to pass around that forms crystal boundary strengthing mechanism, whereas the stir-crush refined particles issue fine particle dispersive strengthing mechanism. However, in the friction stir processing by adding hard ceramics particles, much weak bonds between particles and base metal contributes little material strengthing as dislocations may easily pass around.