Kaiser Aluminum entered into a definitive agreement to purchase substantially all of the assets of Alexco LLC, a Chandler, Ariz.-based manufacturer of hard-alloy extrusions for the aerospace industry. The transaction, worth approximately $90 million, is expected to close in December 2010. Alexco will position Kaiser Aluminum in a market segment that provides a natural complement to its current offering of sheet, plate, cold finish and drawn tube products for aerospace applications.