The effects of laser forming on the mechanical and metallurgical properties of low carbon steel and aluminium alloy samples

The effect of laser forming on the mechanical properties of a material must be understood to manufacture serviceable components. We present a systematic study of the mechanical changes produced when laser forming low carbon steel and aluminium alloy samples (AlSl1010 and AA2024-T3) with increasing applied laser line energy(LE) and number of laser scans. The variation in hardness measured through the specimen thickness was related to the through-thickness temperature attained during forming. For the low carbon steel, the hardness increased if a 'recrystallization' temperature range of approximately 480-520 degrees C was exceeded; for the aluminium alloy, a 'reduced hardness' temperature range of approximately 200-380 degrees C was identified. The extent of affected material depended on the depths at which these temperature ranges were attained, which in turn determined the degradation in the tensile properties of the section. Ultimately, minimum service values of strain for low carbon steel and ultimate tensile strength (UTS) for aluminium alloy were not maintained. The temperature ranges were valid over a wide range of LEs and are independent of system parameters such as laser wavelength and surface preparation. (C) 2010 Elsevier B.V. All rights reserved.