According to an aspect of the present disclosure, a heat-resistant coating composition includes: an inorganic filler which is iron (Fe)-based amorphous alloy powder having an amorphous phase and an average particle diameter of 0.5 μm to 15 μm; and a binder, where the coefficient of thermal expansion of the inorganic filler is lower than the coefficient of thermal expansion of the binder.

In some embodiments, a coating applied to steel reinforcement bar (e.g., steel rebar) that could considerably extend the lifetime of concrete structures by reducing steel rebar corrosion is disclosed. The coating includes a thin, passivating steel (e.g., stainless steel) layer that is applied to the outside of conventional steel rebar. The coating can be applied in-line through metal cold spray manufacturing, which is a high throughput coating technique that can be integrated into existing steel manufacturing plants. Furthermore, a novel, high performance ferritic steel with tailored resistance to corrosion from chlorides is described. The new ferritic steel is distinct from other commercial and experimental steels, and is better suited for coating low-cost steel structures like rebar. Multiple alloying elements including Cr, Al, and Si will each form protective oxides independently, increasing the total amount of protection and extending it over much wider ranges of pH and electrical potential.

Some variations provide a metal matrix nanocomposite composition comprising metal-containing microparticles and nanoparticles, wherein the nanoparticles are chemically and/or physically disposed on surfaces of the microparticles, and wherein the nanoparticles are consolidated in a three-dimensional architecture throughout the composition. The composition may serve as an ingot for producing a metal matrix nanocomposite. Other variations provide a functionally graded metal matrix nanocomposite comprising a metal-matrix phase and a reinforcement phase containing nanoparticles, wherein the nanocomposite contains a gradient in concentration of the nanoparticles. This nanocomposite may be or be converted into a master alloy. Other variations provide methods of making a metal matrix nanocomposite, methods of making a functionally graded metal matrix nanocomposite, and methods of making a master alloy metal matrix nanocomposite. The metal matrix nanocomposite may have a cast microstructure. The methods disclosed enable various loadings of nanoparticles in metal matrix nanocomposites with a wide variety of compositions.

A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.

A composite cemented carbide roll comprising an inner layer made of an iron-based alloy, and an outer layer made of cemented carbide which is metallurgically bonded to an outer peripheral surface of the inner layer; the cemented carbide of the outer layer comprising 55-90 parts by mass of WC particles and 10-45 parts by mass of an Fe-based binder phase having a particular composition; a shaft member and a shaft end member being metallurgically bonded to at least one axial end of the inner layer; the inner layer being made of an iron-based alloy containing 2.0% or more in total by mass of at least one selected from the group consisting of Cr, Ni and Mo; and the shaft member and the shaft end member being made of an iron-based alloy containing 1.5% or less in total by mass of at least one selected from the group consisting of Cr, Ni and Mo.

One aspect is a method of fabricating a housing for an implantable medical device, including forming a first housing portion of metal using an additive manufacturing process such that features are integrated into the first portion. A second housing portion of metal is also formed. The first and second housing portions are joining thereby sealing an internal space of the housing within first and second portions and fully containing the features such that they are hermetically sealed relative to an external space outside the housing.

One aspect is a method of fabricating a housing for an implantable medical device, including forming a first housing portion of metal using an additive manufacturing process such that features are integrated into the first portion. A second housing portion of metal is also formed. The first and second housing portions are joining thereby sealing an internal space of the housing within first and second portions and fully containing the features such that they are hermetically sealed relative to an external space outside the housing.

A method of forming a cutting element comprises disposing diamond particles in a container and disposing a metal powder on a side of the diamond particles. The diamond particles and the metal powder are sintered so as to form a polycrystalline diamond material and a low-carbon steel material comprising less than 0.02 weight percent carbon and comprising an intermetallic precipitate on a side of the polycrystalline diamond material. Related cutting elements and earth-boring tools are also disclosed.

A method of forming a cutting element comprises disposing diamond particles in a container and disposing a metal powder on a side of the diamond particles. The diamond particles and the metal powder are sintered so as to form a polycrystalline diamond material and a low-carbon steel material comprising less than 0.02 weight percent carbon and comprising an intermetallic precipitate on a side of the polycrystalline diamond material. Related cutting elements and earth-boring tools are also disclosed.

The present disclosure provides downhole tools, methods for three dimensional printing hardfacing on such downhole tools, and systems for implementing such methods.