STRUCTURAL AUTOMOTIVE PART MADE FROM AN Al-Zn-Mg-Cu ALLOY PRODUCT AND METHOD OF ITS MANUFACTURE

摘要

A method of manufacturing a formed aluminum alloy body-in-white ("BIW") part of a motor vehicle, the BIW part having a yield strength of more than 500 MPa after being subjected to a paint-bake cycle. The method includes (a) providing a rolled aluminum sheet product of an AlZnMgCu alloy and having a gauge in a range of 0.5 to 4 mm and subjected to a solution heat treatment (SHT) and quenched following SHT, and wherein the SHT and quenched aluminum sheet product has a substantially recrystallized microstructure, (b) forming the aluminum alloy sheet to obtain a formed BIW part, (c) assembling the formed BIW part with one or more other metal parts to form an assembly forming a motor vehicle component, (d) subjecting the motor vehicle component to a paint bake cycle, wherein the aluminum alloy sheet in the formed BIW part has a yield strength of more than 500 MPa.