Metal filaments for fused filament fabrication

A metal filament comprising a plurality of metal particles embedded within a metal matrix, wherein:

• the metal matrix comprises:
• about 30% to about 99.9% tin (w/w);
• about 0% to about 70% bismuth (w/w);
• about 0% to about 5% silver (w/w);
• and
• about 0% to about 5% copper;
• and
• the metal particles comprise:
• about 0% to about 99% tin (w/w);
• about 0% to about 5% silver (w/w);
• and
• about 0.1% to about 100% copper (w/w).