TA15钛合金表面电子束毛化处理的组织特征

利用电子束毛化技术在TAl5薄板(Ti-6Al-2Zr-1Mo-1V)表面生成"毛刺",通过OM,SEM,EDS和XRD分析了"毛刺"的组织、元素成分和性能.研究发现,"毛刺"组织可分为边缘区、中心区、热影响区、基体;边缘区为粗大晶粒和大量片状马氏体,硬度最低;中心区为大晶粒和规则排列的片状马氏体,硬度次低;热影响区晶粒较小,晶界为α相,晶内为平行排列的片状马氏体组织,硬度最高;不同区域的Al含量有明显差异."毛刺"不同区域的硬度主要取决于A1含量和晶粒尺寸.

MICROSTRUCTURE CHARACTERISATION OF PROTRUSIONS BY ELECTRON BEAM SURFI-SCULPT ON THE SURFACE OF TA15 Ti ALLOY

Electron beam surfi-sculpt is a novel surface processing technology,in which electron beam is controlled by magnetic field and deflected quickly over a substrate surface to displace materials in a settled manner,thus producing customized textured surface consisting of an array of protrusions above the original surface and a corresponding array of cavities in the substrate.This technology could be used in dissimilar materials connection between metals and composites,as the protrusions on metal surface would increase the interface area,which results in great improvements in both strength and absorbed energy.It could also be applied to improve the surface coating quality by tailor-making protrusions throughout a component surface so as to enhance the adhesive capacity between coating and substrate,as well as to optimize the stress distribution that occurs in coating process.The application performance of textured surface depends on the microstructure characterisation of protrusions,while the investigation on the microstructures and mechanical properties of the protrusion is lack.In this work,electron beam surfi-sculpt was carried out to produce protrusions on TA15(Ti-6Al-2Zr-1Mo-1V) surface through multi-beam technique. The microstructure features of protrusions were investigated by OM,SEM and XRD,and the weight percentages of alloy elements were analyzed by EDS.In addition,the micro-hardness of the four zones were measured and the results were explained by its microstructure features and weight percentages of alloy elements.It was found that four zones exist in the protrusion,namely edge zone,central zone, heat affected zone(HAZ) and substrate.The edge zone is composed of coarse grain with platelet martensite inside,whose micro-hardness is the lowest.The central zone,whose micro-hardness is the second lowest,is constituted of coarse grain with regular-layed platelet martensite;however,the grain size is smaller than that in the edge zone.The HAZ is characterized of fine grain with boundaryαand parallel-layed short platelet martensite inside,plus the highest micro-hardness.The weight percentages of Al in the HAZ and the substrate were higher than that in the edge zone and the central zone,which,together with different grain size of the four zones,are the two main reasons for the micro-hardness differences of the four zones.