利用ＳＥＭ和ＴＥＭ等方法，对激光表面熔凝处理后ＺＡｌＳｉ１２合金的亚结构进行了分析．实验结果发现，激光重熔可使铝合金组织显著细化，共晶Ｓｉ由粗大的片状转变为珊瑚状．激光熔凝处理不仅使熔区的位错密度和形貌发生根本的改变，而且也使激光熔区周围热影响区内的铝基体中位错密度增加，位错形貌由直线型改变为网络状，同时，有大量的再结晶微晶产生．在激光熔区中，Ｓｉ原子过饱和固溶、偏聚形成富集区，且有大量极细小的Ｓｉ晶体沿＜１１０＞生长方向时效析出．Ｘ射线衍射结果表明，激光熔凝处理可使Ａｌ的点阵常数降低．
Mopohological alteration of Si in eutectic of the surface laser-melted ZAlSi 12 alloy was observed from lath-like into corallite under SEM and TEM. The laser-melted treatment on the ZAlSi 12 alloy surface makes its substruction not only an essential change over dislocation density and mopohology of the laser-melted region, but also an increase of dislocation density in the Al matrix around the heat effecting zone and morphological alteration of dislocation from linear shape into network.Meamwhile, numerous crystallites recrystallize out in the heat effecting zone.In the laser-melted region,α-Al is supersaturated and solutionized with Si atoms. The Si atoms segregated to form the enriched area, and a great many very fine Si crystals precipitated out along <110> direction. X-ray diffraction analysis showed that the lattiee parameters of Al may be decreased by the laser-melted treatment.
参考文献
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| [4] | FerraroF,NannettiCA,CampelloM,SeninA,In:QuenzerAed．,Proc．3rdInt．ConfonLasersinManufacturing,3-5June,1986,Paris,BedfordUK:IFS(Publications)Ltd,1986:2332LiangGongying,ZhouJiayin,ZhengQiguang．ChineseJournalofLasers,1993 |
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