elements aluminium and oxygen the contents of these elements can be at least 0 02 by weight preferably at least 0 05 by weight in a ti alloy according to the invention the elements belonging to the group mo ta nb zr mn cr co ni cu v si h stabilise the u03b2 phase of ti alloys to use this effect at least one of these elements should be present in contents of at least 0 03 to 2 by weight the invention will be described in more detail hereinafter with reference to an embodiment firstly a titanium alloy according to the invention which in addition to titanium and unavoidable impurities contained 0 4 by weight si 0 2 by weight fe and 0 6 by weight la is melted and rolled to form a ti strip with a thickness of 1 25 mm to avoid absorption of oxygen according to the method known from de 101 03 169 a1 and based on the ti alloy according to the invention a composite e was then produced by applying by roll bonding a 0 1 mm thick al foil as a covering layer to the ti strip being used as a base layer of the composite the al covering layer applied to the titanium base material in this way had a thickness of 0 04 mm following roll bonding after roll bonding components for the exhaust gas system of an internal combustion engine used in a car were formed from the composite e without having been subjected.