Abstract: A method of making an aerospace component such as a spar for an aircraft wing is disclosed. The method includes placing two billets of different alloy in abutting relation, there being no voids or channels formed therebetween, partial penetration friction stir welding together the two billets from opposing sides of the billets, the welds so formed being separated by a central region formed partly by one billet and partly by the other billet, and then machining away material. The machining may be performed so as to leave no portion having a partial penetration friction stir weld, so as to remove all of the central region, and so as to form a multi-alloy spar having at least one transverse web section having a slot formed at least in part by the removal of the central region.

Abstract: A method of making an aerospace component such as a spar for an aircraft wing is disclosed. The method includes placing two billets of different alloy in abutting relation, there being no voids or channels formed therebetween, partial penetration friction stir welding together the two billets from opposing sides of the billets, the welds so formed being separated by a central region formed partly by one billet and partly by the other billet, and then machining away material. The machining may be performed so as to leave no portion having a partial penetration friction stir weld, so as to remove all of the central region, and so as to form a multi-alloy spar having at least one transverse web section having a slot formed at least in part by the removal of the central region.

Abstract: Two aluminium alloy work-pieces are welded together. Firstly, a portion (2) of each work-piece (1) is prepared, the preparation including the performance of a surface treatment, such as friction stir welding, that results in a region (A) extending from the exterior surface into the work-piece having a grain structure that is finer than the grain structure of the work-piece outside (region C) that region. Then the work-pieces are welded together by means of a fusion welding process, such as electron beam welding, that joins the respective prepared portions (2) of the two work-pieces (1). The preparation of the work-pieces is so performed that said region (A) extends into the work-piece to a depth that exceeds the depth of material (region D) that is caused to melt during the fusion welding process.