A method for thermal processing bullets to yield a refined grain structure, the method includes obtaining one or more bullets, disposing the one or more bullets within a chamber having a temperature gradient between ambient temperature and cryogenic temperature, the chamber having a plurality of temperature zones, moving the one or more bullets between the plurality of temperature zones of the chamber at a predetermined rate, and returning the one or more bullets to the ambient temperature.

An object of the present invention is to provide a dissimilar metal joined material that has corrosion resistance that can prolong life resulting from corrosion and has a small difference from original characteristics. There is provided a dissimilar metal joined material including: a clad material including a high thermal expansion layer composed of an alloy containing Mn, and a low thermal expansion layer composed of an alloy containing Ni, the low thermal expansion layer being joined directly to the high thermal expansion layer or via an intermediate layer; and a corrosion resistant plating layer provided on at least a surface of the high thermal expansion layer, the corrosion resistant plating layer having a thickness of 10 nm to 120 nm.

A method for thermal processing bullets to yield a refined grain structure, the method includes obtaining one or more bullets, disposing the one or more bullets within a chamber having a temperature gradient between ambient temperature and cryogenic temperature, the chamber having a plurality of temperature zones, moving the one or more bullets between the plurality of temperature zones of the chamber at a predetermined rate, and returning the one or more bullets to the ambient temperature.

One embodiment described herein is directed to a method involving depositing a seed layer on a substrate, the seed layer comprising A1 phase FePt with a ratio of Pt of Fe greater than 1:1. A main layer is deposited on the seed layer, the main layer comprising A1 phase FePt with a ratio of Pt to Fe of approximately 1:1. A cap layer is deposited on the main layer, the cap layer comprising A1 phase FePt with a ratio of Pt to Fe of less than 1:1. The seed, main and cap layers are annealed to convert the A1 phase FePt to L1.sub.0 phase FePt having a graded FePt structure of varying stoichimetry from approximately Fe.sub.50Pt.sub.50 adjacent a lower portion of the structure proximate the substrate to Fe.sub.>50Pt.sub.<50 adjacent an upper portion of the structure opposite the lower portion.

One embodiment described herein is directed to a method involving depositing a seed layer on a substrate, the seed layer comprising A1 phase FePt with a ratio of Pt of Fe greater than 1:1. A main layer is deposited on the seed layer, the main layer comprising A1 phase FePt with a ratio of Pt to Fe of approximately 1:1. A cap layer is deposited on the main layer, the cap layer comprising A1 phase FePt with a ratio of Pt to Fe of less than 1:1. The seed, main and cap layers are annealed to convert the A1 phase FePt to L1.sub.0 phase FePt having a graded FePt structure of varying stoichimetry from approximately Fe.sub.50Pt.sub.50 adjacent a lower portion of the structure proximate the substrate to Fe.sub.>50Pt.sub.<50 adjacent an upper portion of the structure opposite the lower portion.

A method for thermal processing bullets to reduce adhesive stress, the method includes obtaining one or more bullets configured to be propelled down a gun barrel, disposing the one or more bullets within a chamber having a temperature gradient between ambient temperature and cryogenic temperature, the chamber having a plurality of temperature zones, moving the one or more bullets between the plurality of temperature zones of the chamber, and returning the one or more bullets to the ambient temperature to reduce adhesive stress between the bullets and the gun barrel.