Page 102 - 机械工程材料2024年第十一期

张 杰，等：成形试样形状和尺寸对激光选区熔化成形钛合金残余应力的影响

Effect of Formed Specimen Shape and Size on Residual Stress of Titanium Alloy
Formed by Selective Laser Melting

ZHANG Jie 1, 2, 3 , LIU Chuan , HU Quandong 1, 2, 3 , LIU Qi 1, 2, 3 , LI Huaixue 1, 2, 3 , XU Jiancheng 1, 2, 3
4
(1. AVIC Manufacturing Technology Institute, Beijing 100024, China; 2. Beijing Key Laboratory of High Power Beam Additive
Manufacturing Technology and Equipment, Beijing 100024, China; 3. Aeronautical Key Laboratory for
Additive Manufacturing Technologies, Beijing, 100024, China；4. School of Mechatronic
Engineering and Automation, Foshan University, Foshan 528225, China)

Abstract: With TC4 titanium alloy powder as raw materials, four types of specimens with different shapes and
sizes, including the columnar specimen with diameter of 16 mm, the fatigue specimen with diameter of 7 mm in parallel
section and diameter of 16 mm in clamping section, the plate specimens with thickness of 10 mm and 22 mm were directly
formed by selective laser melting (SLM) . The z-directional (forming direction) residual stress of the specimen was measured
by the contour method. The effects of specimen shape and size on residual stress were analyzed. The results show that
the internal residual stresses of SLM formed specimens were compressive stresses, and the surface residual stresses were
tensile stresses. The distribution shape of residual compressive stresses was similar to the shape of the specimen cutting
section, it was nearly circular and nearly rectangular, respectively. Compared with the 22 mm-thick plate specimen, the
distribution span and amplitude of the internal compressive stress on the centerline in the thickness direction of the 10 mm-
thick plate were lower, the distribution span of the internal compressive stress on the centerline in the width direction
was unchanged, and the peak value of the compressive stress was reduced by nearly 1/2. The internal compressive stress
distribution and amplitude of SLM formed specimen were greatly affected by the shape and size of the specimen, which was
attributed to the different constraints in forming of specimens with different shapes and sizes.
Key words: additive manufacturing; selective laser melting; residual stress; titanium alloy; specimen shape and size

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