利用激光局部硬化效应提高2B06铝合金板材拉深成形性研究

针对2B06铝合金复杂零件成形困难问题，提出了利用激光热处理局部硬化提高板材成形性的思路。在通过激光热处理试验研究了铝合金板的激光硬化效应的基础上，采用数值模拟计算了铝合金板激光热处理过程中激光光斑路径和其周边热影响区域的峰值温度场，并通过实际测温验证了其准确性。提出并构建了耦合性能梯度的差性坯料模型，对激光局部硬化的杯形件拉深成形性进行了模拟和试验研究。结果表明，激光扫描方式可以形成稳定的梯度温度场并对周边非加热区影响较小，且可以通过多道次扫描方式设计不同宽度范围的大梯度差性板材坯料。力学性能试验表明激光热处理可以有效地提高铝合金的局部加工硬化能力，这种效应可以有效抑制杯形件拉深时圆角大变形区的减薄，从而提升了板材的拉深性能。在上述基础上，将激光局部热处理用于2B06铝合金航空复杂口框零件的成形，通过设计激光处理路径和参数，获得合理的局部硬化区域，可有效地避免在加强筋处出现过度减薄导致的破裂，大大提高复杂零件的成形性。

Study on Improving the Formability of 2B06 Aluminum Alloy Sheet by Local Hardening Effect Using Laser Heat Treatment

Aiming at the difficulty of forming complex parts of 2B06 aluminum alloy, the idea of using local hardening by laser heat treatment to improve the formability of sheet metal was put forward. Based on the experimental study of hardening effect on aluminum alloy sheet by laser heat treatment, the peak temperature field of laser spot path and its surrounding heat-affected area was calculated by numerical simulation, and its accuracy was verified by actual temperature measurement. A sheet billet model coupled with mechanical property gradient was proposed and constructed to study the deep drawing formability of cup parts with laser local hardening using both simulation and experimental methods. The results show that the laser scanning method can form a stable gradient temperature field and has little influence on the surrounding non-heated area, and big property gradient sheet blanks with different widths can be designed by multi-pass scanning. Mechanical properties tests show that laser heat treatment can effectively improve the local hardening ability of aluminum alloy. This effect can effectively prevent the thinning of large deformation area at round corners during cup drawing, thus improving the drawing formability of sheet metal. Based on the above mentioned, the laser local heat treatment is applied to the forming of 2B06 aluminum alloy aviation complex frame parts. By designing the laser treatment path and parameters, the reasonable local hardening area can be obtained, which can effectively avoid the crack caused by excessive thinning at the reinforcement area, and greatly improve the formability of complex parts.