Welded nickel alloy double-cantilever beam crack growth sensor and method for its fabrication

A method for fabricating a double-cantilever beam crack growth sensor, comprising the following steps:

• forming a first block of a first type of nickel-based alloy;
• depositing a predetermined thickness of a nickel-based weld alloy on top of said first block to form a bi-metallic test block, said weld alloy having a nickel-based composition different than that of said nickel-based alloy of said first type;
• milling the top surface of said weld alloy of said test block;
• preparing the milled top surface of said weld alloy for welding;
• forming a second block of said nickel-based alloy of said first type;
• welding said second block to said weld alloy to form a three-layer block;
• and
• machining said three-layer block to form first and second cantilever beams comprising said nickel-based alloy of said first type and a crack growth section made of said weld alloy having a dendritic microstructure wherein the dendrites are substantially parallel to the general direction in which said first and second cantilever beams extend.