Aluminium bolts are a great way to add little splashed of colour to your bike and/or save some weight - but we only recommend they are used sensibly in low-stress areas.
Many riders (ourselves included!) have used them for long periods of time as headset pre-load bolts, brake clamp bolts/nuts and crank bolts without problems. We always recommend using a high quality allen key set and plenty of copper grease for fitting.
TartyBikes Ltd, Units 3-4, Club Street, Bamber Bridge, Preston, PR5 6FN