A method of layer-by-layer construction of a metallic part comprising: supplying particles of an alloy, wherein the alloy consists of one of the following compositions (a) or (b): (a) Fe at 54.5 to 69.5 wt. %; B at 0.5 to 3.0 wt. %; Cr at 16.5 to 20.5 wt. %; Mn at 1.0 to 2.5 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; Ni at 10.5 to 14.0 wt. %, and inevitable impurities; (b) Fe at 55.5 to 75.2 wt. %; B at 0.5 to 3.0 wt. %; Cr at 17.0 to 22.0 wt. %; Mn at 0.3 to 3.0 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; and Ni at 5.0 to 10.0 wt. %, and inevitable impurities; supplying a substrate; applying one or more layers of said alloy onto said substrate by melting said particles into a molten state to form a molten alloy and cooling said molten alloy at a rate of 10 3 to 10 8 K/sec to form a solidified layer of said elements wherein each of said solid layers has a thickness as formed of 3.0 to 200.0 microns, wherein the solidified layer after cooling includes said elements defining a primary dendritic austenite phase and an initial level of interdendritic lamellar boride phases with lamella width of less than 0.1 microns; heat treating said alloy at a temperature in the range of 800 to 1200° C for a time period of 30-1000 minutes to consolidate and grow said boride phases by diffusion of said elements from said primary phase into spheroidized boride phases ranging in diameter from about 0.2 microns to 5 microns; and optionally removing said substrate to form a free-standing metallic part; wherein said one or more solid layers indicates an abrasion resistance as measured by ASTM G65-04 Procedure A of less than or equal to 175 mm 3. supplying particles of an alloy, wherein the alloy consists of one of the following compositions (a) or (b): (a) Fe at 54.5 to 69.5 wt. %; B at 0.5 to 3.0 wt. %; Cr at 16.5 to 20.5 wt. %; Mn at 1.0 to 2.5 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; Ni at 10.5 to 14.0 wt. %, and inevitable impurities; (b) Fe at 55.5 to 75.2 wt. %; B at 0.5 to 3.0 wt. %; Cr at 17.0 to 22.0 wt. %; Mn at 0.3 to 3.0 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; and Ni at 5.0 to 10.0 wt. %, and inevitable impurities; (a) Fe at 54.5 to 69.5 wt. %; B at 0.5 to 3.0 wt. %; Cr at 16.5 to 20.5 wt. %; Mn at 1.0 to 2.5 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; Ni at 10.5 to 14.0 wt. %, and inevitable impurities; (b) Fe at 55.5 to 75.2 wt. %; B at 0.5 to 3.0 wt. %; Cr at 17.0 to 22.0 wt. %; Mn at 0.3 to 3.0 wt. %; Si at 2.0 to 5.0 wt. %; C at 0.0 to 0.5 wt. %; and Ni at 5.0 to 10.0 wt. %, and inevitable impurities; supplying a substrate; applying one or more layers of said alloy onto said substrate by melting said particles into a molten state to form a molten alloy and cooling said molten alloy at a rate of 10 3 to 10 8 K/sec to form a solidified layer of said elements wherein each of said solid layers has a thickness as formed of 3.0 to 200.0 microns, wherein the solidified layer after cooling includes said elements defining a primary dendritic austenite phase and an initial level of interdendritic lamellar boride phases with lamella width of less than 0.1 microns; heat treating said alloy at a temperature in the range of 800 to 1200° C for a time period of 30-1000 minutes to consolidate and grow said boride phases by diffusion of said elements from said primary phase into spheroidized boride phases ranging in diameter from about 0.2 microns to 5 microns; and optionally removing said substrate to form a free-standing metallic part; wherein said one or more solid layers indicates an abrasion resistance as measured by ASTM G65-04 Procedure A of less than or equal to 175 mm 3.