Nickel-Copper Solid Solution

Nickel and copper mix completely in the solid state, so you get a homogeneous solid solution. That's good for welding because you don't have different phases in the weld that could later corrode or crack. It's important not to cool the weld too quickly, otherwise you risk cracks. And don't overdo the heat either, or the structure will become uneven and the weld tough. Just keep the temperature control clean and even, then it'll be fine.