Edit: To clarify, the Title is simply the title, the actual question is stated below.
It is a fantasy world where Magic has been fading away for a millennium and a half. Lead naturally disrupts magic, such as ending/negating Mage Armour (D&D) when struck. Mercury is discovered to create extremely effective Dragon slaying qualities when combined with Lead. Assuming an Italian renaissance level of scientific understanding and technology (if specifics are needed, imagine Leonardo Da Vinci attempting to make it), and with no magical processes:
Would a Lead+Mercury weapon be possible to forge (albeit incredibly heavy and worth less than garbage against steel), and/or be bonded to create a steel (or other metal) alloy for an actual effective weapon?
Tl;Dr Do I need to make up some fake science/magic excuse for lead and mercury forged weapons?