激光粉末床熔融成形AlSi10Mg铝合金复杂流道构件研究

Study on AlSi10Mg Alloy with Complex Flow Channels by Laser Powder Bed Fusion

采用激光粉末床熔融技术制备不同截面与截面尺寸的长直流道试样以及复杂流道产品。研究结果表明,当流道截面尺寸小于2 mm时,激光粉末床熔融成形后流道的收缩而对残余粉末进行挤压,这将导致流道内残余粉末难以完全清除。此外,随着流道截面的增大,圆形流道上表面结合处呈现出表面质量变差的现象,而屋脊形截面流道由于倾斜角度保持不变而呈现较好的成形质量及尺寸精度。激光深穿透至非成形区粉末是造成流道上部区域粘附粉末颗粒的重要原因,而通过磨粒流、高压气流及水流等方式可以对其去除。结果表明,基于激光粉末床熔融技术设计与成形的复杂流道散热元件经X射线检测和计算机断层成像检测均无裂纹及残余粉末,并通过了2 MPa压力、保压5 min的耐压检测。最后,初步构建了复杂流道类构件的“设计—成形—检测”一体化流程。

The specimens with straight channels and the product with complex channels were manufactured by laser powder bed fusion.The results showed that when the diameter of the channel was less than 2 mm,the remaining powder inside the channels could not be removed completely due to the shrinkage of the flow channels after fabricated.In addition,the forming quality of the top surface of the circular channels became worse,with the increase of the diameter while the forming quality and dimensional accuracy for ridge shape channels still kept better with the increase of the size of the section,since the inclination angle of the inner surface was a fixed value.Meanwhile,the semi-melted powder particles adhered to the upper region of the flow channels caused by the deep penetration of the laser into the powder in the nonforming region could be removed by abrasive flow machining,high pressure airflow or water.The test results of the laser powder bed melting product with complex flow channels indicated that there were no defects such as crack or remaining powder by X-ray and computed tomography test.And the pressure test suggested that the product with complex flow channels was not damaged or leaked when the pressure reached 2 MPa for 5 min.Finally,the processes“design-formtest”were successfully established for the products with complex flow channels.