Process for making 7xxx series aluminum/fiber reinforced polypropylene hybrid part for automotive crash absorption application

A method of making a composite laminate object, the composite laminate object comprising an extrusion grade 7xxx Al substrate and a fiber reinforced polypropylene layer adhesively laminated to the 7xxx Al substrate, the method comprising:

• shaping and cutting an extruded 7xxx aluminum member to form a 7xxx Al substrate having a shape;
• assembling a layered arrangement of the 7xxx Al substrate, an adhesive film and a fiber reinforced polypropylene preform, wherein the fiber reinforced polypropylene preform comprises reinforcing fibers and polypropylene resin;
• heating the layered arrangement to a temperature of 160° C. to 175° C. to melt the polypropylene resin and activate the adhesive film;
• applying pressure to at least a surface of the fiber reinforced polypropylene preform to mold the fiber reinforced polypropylene preform to the shape of the 7xxx Al substrate and obtain a semi-finished laminate object;
• cooling the semi-finished laminate object to 90° C.;
• optionally, cooling the semi-finished laminate object to 20° C. to 30° C. for inventory storage;
• heat treating the semi-finished laminate object at 90° C. for 2 to 8 hours;
• then heat treating the semi-finished laminate object at 130° C. to 150° C. for 8 to 16 hours to provide a heat treated laminate object;
• and
• cooling the heat treated laminate object to obtain the composite laminate object.