Method of improving mechanical properties of alloy parts

Claim 1

A method of improving the mechanical properties of an age-hardenable alloy part characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service, said alloy having a melting point of at least about 1000° C. which comprises, subjecting said age-hardenable alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardenable alloy in excess of 50% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of over 20° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part heat treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.

Claim 2

A method of improving the mechanical properties of an age-hardenable alloy part characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service, said alloy having a melting point of at least about 1000° C. which comprises, subjecting said age-hardenable alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardenable alloy in excess of 50% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of over 20° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part heat treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.

Claim 8

A method of improving the mechanical properties of an age-hardened alloy part selected from the group consisting of iron-base, nickel-base, cobalt-base, and titanium-base alloys of melting point in excess of 1000° C. characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service which comprises, subjecting said alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardened alloy ranging from over 50% to about 95% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of at least about 25° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.

Claim 9

A method of improving the mechanical properties of an age-hardened alloy part selected from the group consisting of iron-base, nickel-base, cobalt-base, and titanium-base alloys of melting point in excess of 1000° C. characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service which comprises, subjecting said alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardened alloy ranging from over 50% to about 95% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of at least about 25° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.

Claim 13

A method of improving the mechanical properties of an age-hardenable superalloy part characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service, said alloy having a melting point of at least about 1000° C. which comprises, providing at least one part of composition containing by weight up to about 30% Cr, up to about 20% of a metal from the group consisting of Mo and W, up to about 10% of a metal from the group consisting of Cb and Ta, up to about 1% C, up to about 10% of a metal from the group consisting of Ti and Al, the total amount of Ti and Al not exceeding about 12%, up to about 20% Fe, up to about 2% Mn, up to about 2% Si, up to about 0.2% B, up to about 1% Zr, up to about 2% Hf, and essentially the balance at least about 45% by weight of at least one metal selected from the group consisting of nickel and cobalt, subjecting said age-hardenable alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardenable alloy in excess of 50% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of over 20° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part heat treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.

Claim 14

A method of improving the mechanical properties of an age-hardenable superalloy part characterized by the presence of such structural defects as cast micropores and/or grain boundary voids or microcracks formed during high temperature service, said alloy having a melting point of at least about 1000° C. which comprises, providing at least one part of composition containing by weight up to about 30% Cr, up to about 20% of a metal from the group consisting of Mo and W, up to about 10% of a metal from the group consisting of Cb and Ta, up to about 1% C, up to about 10% of a metal from the group consisting of Ti and Al, the total amount of Ti and Al not exceeding about 12%, up to about 20% Fe, up to about 2% Mn, up to about 2% Si, up to about 0.2% B, up to about 1% Zr, up to about 2% Hf, and essentially the balance at least about 45% by weight of at least one metal selected from the group consisting of nickel and cobalt, subjecting said age-hardenable alloy part to HIP processing in an autoclave at superatmospheric pressure and at an elevated solution temperature of said age-hardenable alloy in excess of 50% of the absolute melting point of said alloy for a time at least sufficient to effect substantial removal of said structural defects by heat and densification, heat treating said alloy part in situ by rapidly cooling it at a rate of over 20° C. per minute to below the age-hardening temperature range of said alloy while maintaining said part under superatmospheric isostatic pressure, and then age-hardening said alloy following completion of said HIP processing, whereby said part is improved in mechanical properties as compared to the same part heat treated by rapid cooling said alloy part outside of said autoclave and aging it following conventional HIP processing.