TIG电弧增材制造5356铝合金微观组织与拉伸性能

Microstructure and tensile properties of 5356 aluminum alloy by TIG wire arc additive manufacturing

针对TIG电弧增材制造5356铝合金试样不同区域微观组织及性能变化开展研究.结果表明,试样结合层与沉积层水平交替呈现,底部区域沉积层宽度最大(~2.4 mm),中间稳定区最小(~1.6 mm);沉积层组织均以等轴晶为主,在灰色基体上弥散分布黑色β-Al3Mg2第二相,并伴有少量Mg2Si和(FeMn)Al6金属间化合物,结合层存在大量气孔及缩孔等缺陷;底部区域沉积层晶粒尺度最小,而结合层缺陷最多.不同区域水平方向强塑性无明显差异(R m=274 MPa,A=32.3%),垂直方向强度与水平方向近似相等,但断后伸长率下降到26%,两个方向拉伸断口均以等轴韧窝为主.3个区域沉积层硬度值稳定,底部沉积层硬度值略高于其余区域,而结合层硬度值波动明显.

The microstructure and properties of 5356 aluminum alloy sample manufactured by TIG wire arc additive manufacturing in the different regions were studied.The results showed that interlayer of sample alternated with the deposition layer horizontally,the width of deposition layer at the bottom was the largest(~2.4 mm),and the middle stable region was the smallest(~1.6 mm).The deposition layer consisted of equiaxial grains,and the black second phaseβ-Al3 Mg2 and a small amount of intermetallic compounds Mg2 Si and(FeMn)Al6 diffused on the gray matrix.A large number of pores and shrinkage holes appeared at the interlayer.The deposition layer at the bottom had the smallest grain size,but the interlayer had the most defects.The strength and plasticity were approximately equal in the horizontal direction at the different regions(Rm=274 MPa,A=32.3%).The strength in vertical direction was approximately equal to that in horizontal direction,but the elongation dropped to 26%.The tensile fracture was mainly composed of equiaxial dimples in both directions.The hardness of the deposition layer at the three regions was stable,and the hardness at the bottom was slightly higher than that of the rest regions,while the hardness of the interlayer fluctuated significantly.