Preservation of strain in iron nitride magnet

A method comprising:

• applying, at a first temperature, a layer of material to a strained iron nitride-containing workpiece comprising at least one Fe16N2 phase domain, wherein the strained iron-nitride workpiece has dimensions of at least 0.1 mm, such that an interface is formed between the layer and the iron nitride-containing workpiece, wherein the material has a different coefficient of thermal expansion than the iron nitride-containing workpiece;
• and
• bringing the iron nitride-containing workpiece and the layer of material from the first temperature to a second temperature different than the first temperature to cause at least one of a compressive force or a tensile force on the iron nitride-containing workpiece such that a strained state is preserved to provide a strained iron-nitride workpiece, wherein the at least one of the compressive force or the tensile force preserves strain in at least the portion of the strained iron nitride-containing workpiece comprising the at least one Fe16N2 phase domain.