Heat exchangers, heat exchanger tubes, and additive manufacturing cold spray processes for producing the same

A method for producing a heat exchanger, comprising:

• obtaining a Non-Equilibrium (NEA) feedstock powder comprised of an alloy matrix throughout which a first minority constituent is dispersed, the first minority constituent precipitating from the alloy matrix when the NEA feedstock powder is exposed to temperatures exceeding a critical temperature threshold (TCRITICAL) for a predetermined time period;
• utilizing a cold spray process to at least partially form Heat Exchanger (HX) tubes from the NEA feedstock powder;
• and
• installing the HX tubes in the heat exchanger by placing the HX tubes in contact with a header structure and utilizing a low temperature joint forming process to seal selected interfaces between the HX tubes and the header structure, while maintaining peak temperatures to which the HX tubes are exposed to below TCRITICAL, and TCRITICAL is less than a melt point of the NEA feedstock powder;
• wherein the cold spray process is performed such that:
• (i) the HX tubes are exposed to a maximum temperature (TSPRAY_MAX) during the cold spray process, and (ii) TSPRAY_MAX is maintained below TCRITICAL to substantially preserve a non-equilibrium state of the NEA feedstock powder through the cold spray process.