中文摘要：

金属板料激光热应力弯曲成形是一种新型非接触式、无模和无外力、且无回弹的高度柔性成形技术，以室温下难变形的航空用TC4钛合金板料作为研究对象，采用大功率COz激光加工设备，从影响板料激光弯曲成形的相关工艺参数和板料几何尺寸角度出发，进行了较为系统的试验研究，并对激光热源辐射扫描对板料显微组织的影响进行了分析。试验结果表明，不同厚度的TC4钛合金板料其激光热应力弯曲成形角度均随激光功率和扫描次数的增加、扫描速度和激光光斑直径的减小而增大。随着板料宽度的增大，2mm和3mm厚度的板料其激光热应力弯曲成形角度分别呈减小和增大的趋势。一定程度上，累积能量密度的增大才能诱发产生较大的弯曲成形角度，但累积能量密度的选择需兼顾板料表面质量和弯曲成形效率。激光热辐射对板料扫描区域的组织产生一定程度的影响，TC4钛合金板料激光扫描中心区域组织呈现多种形态。

英文摘要：

Laser forming of sheet metal by thermal stress is a highly flexible forming technique of a new type of non-contact, no mold and no external force, and no springback. TC4 titanium alloy, as a difficult deformation material for the room temperature is used in the research. In the laser bending experiment of TC4-sheet metal, a high power COz laser processing equipment was used, and the effect of laser bending process parameters and the sheet dimension on bending angle are studied systematically. The evolution of microstructure for laser radiation scanning zone is also analyzed. The results show that, the laser thermal stress bending angle for TC4 titanium alloy sheet metal with different thickness increases with the increase of the laser power and the number of passes, and decreases with the increase of scanning velocity and the diameter of laser spot. Laser bending an- gle for the thickness of 2 mm and 3 mm sheet decrease and increase with the increase of the width of the sheet respectively. To a certain extent, the higher the accumulated energy is, the larger density bending angle is. The accumulated energy density se lection should be selected in considering the surface quality of sheet metal and forming efficiency. The effect of laser radiation on the microstructure for irradiated area is produced, and there are many microstructure forms in the laser the irradiated zone of TC4 titanium alloy.