Ultra-longlife, high formability brazing sheet

A multi-layered brazing sheet comprising:

• a core comprising a 3xxx series alloy comprising less than 0.18 wt. % Si, up to about 0.8 wt. % Fe, about 0.5− to about 1.6 wt. % Mn, up to about 1.0 wt. % Cu, about 0.01 to about 1.5 wt. % Mg, up to about 0.3 wt. % Cr and up to 0.25 wt. % Ti;
• an aluminum alloy interliner having a thickness of less than 60 microns positioned on one side of said core, and a braze cladding comprising a 4xxx series alloy positioned on the other side of said interliner, wherein upon brazing of said sheet to a component, core develops a continuous dense Mn-containing dispersoid band at the interface between said core and said interliner resulting from diffusion of Si from said cladding into said core.