激光半模冲击成形中板料反向变形现象研究

为了研究激光半模冲击成形在工业领域的实际应用,利用钛合金薄板作为试样进行波形零件的冲击试验,冲击过程中发现试样局部区域产生了反向变形,尤其在薄板中心区域反向变形现象更为严重.板料的反向变形使板料不能与凹模密切贴合,严重影响了冲击成形的质量.通过分析发现,由于激光能量较高,使板料与凹模凹陷处接触时的残余速度过高,从而导致板料与凹模发生剧烈碰撞.当板料因碰撞产生的反向运动速度大于板料反向屈服的速度阈值时将会产生影响成形质量的反向变形.通过调整激光能量避免了反向变形的发生,得到了理想的波形零件.实验与分析的结果表明,在满足半模冲击成形塑性变形量的基础上,采用较低的激光能量,既可避免反向变形的产生,又可保证半模冲击成形的质量.

Investigation of inverse deformation in laser shock forming with half die

In order to investigate the application of laser shock forming with half die in industry,experiments were executed with titanium alloy sheet.Inverse deformation of sample in its partial area was found in laser shock forming process,especially it was more obvious in the center of concave die.The inverse deformation heavily affected the shock forming quality because it made the sheet couldn't touch concave die closely.According to results of experiment and analyses,the sheet with great speed hits the concave die strongly when it touches concave die if laser energy is higher than the needs of deformation,so the sheet obtains an inverse velocity through hitting,and the inverse deformation take place if the inverse velocity beyond the speed threshold value of plastic deformation,which has great effect on the quality of shock forming.A good quality work piece was obtained after adjusting laser energy,which shows that inverse deformation can be avoided under lower laser energy.