Castable high-temperature Ce-modified Al alloys

A method of making a cast alloy comprising the steps of:

• a. heating preselected amounts of aluminum and at least one additional alloying element selected from the group consisting of silicon, zinc, iron, titanium, zirconium, vanadium, magnesium, copper, and nickel to a molten state to form a melt;
• b. degassing said melt with a reactive gas in order to purge said melt of undesirable dissolved materials and bring the melt to greater than 90% theoretical density;
• c. further degassing said melt with a nonreactive gas to remove the reactive gas;
• d. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• e. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 70% theoretical density, repeat steps b, c, d, and e;
• ii. exceeds 70% theoretical density, but does not exceed 90% theoretical density, repeat steps c, d, and e;
• iii. exceeds 90% theoretical density, go to step f;
• f. adding to said melt a preselected amount of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal;
• g. degassing said melt with a nonreactive gas;
• h. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• j. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps g, h, and j;
• ii. exceeds 90% theoretical density, go to step k;
• and
• k. transferring said melt into a casting mold to form a cast alloy comprising:
• aluminum and from about 5 to about 30 weight percent of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said cast alloy having a strengthening Al11X3 intermetallic phase in an amount in the range of from about 5 to about 30 weight percent, wherein X is at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said Al11X3 intermetallic phase having a microstructure comprising at least one morphological feature selected from the group consisting of lath features and rod features, said features having an average thickness of no more than 700 um and an average lath spacing of no more than 10 um, said microstructure further comprising an eutectic microconstituent that comprises more than about 10 volume percent of said microstructure.

A method of making a cast alloy comprising the steps of:

• a. heating a predetermined amount of aluminum;
• b. degassing said melt with a reactive gas in order to purge said melt of undesirable dissolved materials;
• c. further degassing said melt with a nonreactive gas to remove the reactive gas;
• d. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 70% theoretical density, repeat steps c and d;
• ii. exceeds 70% theoretical density, but does not exceed 90% theoretical density, repeat steps b, c, and d;
• iii. exceeds 90% theoretical density, go to step f;
• e. adding to said melt a predetermined amount of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal;
• f. degassing said melt with a nonreactive gas;
• g. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• h. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps f, g, and h;
• ii. exceeds 90% theoretical density, go to step j;
• j. adding a predetermined amount of at least one additional alloying element selected from the group consisting of silicon, zinc, iron, titanium, zirconium, vanadium, magnesium, copper, and nickel to said melt;
• k. degassing said melt with a nonreactive gas;
• l. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• m. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps k, l and m;
• ii. exceeds 90% theoretical density, go to step n;
• and
• n. transferring said melt into a casting mold to form a cast alloy comprising:
• aluminum and from about 5 to about 30 weight percent of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said cast alloy having a strengthening Al11X3 intermetallic phase in an amount in the range of from about 5 to about 30 weight percent, wherein X is at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said Al11X3 intermetallic phase having a microstructure comprising at least one morphological feature selected from the group consisting of lath features and rod features, said features having an average thickness of no more than 700 um and an average lath spacing of no more than 10 um, said microstructure further comprising an eutectic microconstituent that comprises more than about 10 volume percent of said microstructure.

A method of making a cast alloy comprising the steps of:

• a. heating predetermined amounts of aluminum and at least one additional alloying element selected from the group consisting of silicon, iron, titanium, zirconium, vanadium, copper, and nickel to a molten state to form a melt;
• b. degassing said melt with a reactive gas in order to purge said melt of undesirable dissolved materials;
• c. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• d. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps b, c, and d;
• ii. exceeds 90% theoretical density, go to step e;
• e. adding to said melt a predetermined amount of at least one material selected from the group consisting of magnesium and zinc;
• f. degassing said melt with a reactive gas in order to purge said melt of undesirable dissolved materials;
• g. further degassing said melt with a nonreactive gas to remove the reactive gas;
• h. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• j. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 70% theoretical density, repeat steps f, g, h, and j;
• ii. exceeds 70% theoretical density, but does not exceed 90% theoretical density, repeat steps g, h, and j;
• iii. exceeds 90% theoretical density, go to step k;
• k. adding to said melt a predetermined amount of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal;
• l. degassing said melt with a nonreactive gas;
• m. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• n. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps l, m and n;
• ii. exceeds 90% theoretical density, go to step o;
• and
• o. transferring said melt into a casting mold to form a cast alloy comprising:
• aluminum, up to about 12 weight percent magnesium, up to about 7 weight percent zinc, and from about 5 to about 30 weight percent of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said cast alloy having a strengthening Al11X3 intermetallic phase in an amount in the range of from about 5 to about 30 weight percent, wherein X is at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said Al11X3 intermetallic phase having a microstructure comprising at least one morphological feature selected from the group consisting of lath features and rod features, said features having an average thickness of no more than 700 um and an average lath spacing of no more than 10 um, said microstructure further comprising an eutectic microconstituent that comprises more than about 10 volume percent of said microstructure.

A method of making a cast alloy comprising the steps of:

• a. heating predetermined amounts of aluminum and at least one additional alloying element selected from the group consisting of silicon, iron, titanium, zirconium, vanadium, copper, and nickel to a molten state to form a melt;
• b. degassing said melt with a reactive gas in order to purge said melt of undesirable dissolved materials;
• c. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• d. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps b, c, and d;
• ii. exceeds 90% theoretical density, go to step e;
• e. adding to said melt a predetermined amount of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal;
• f. degassing said melt with a nonreactive gas;
• g. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• h. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps f, g, and h;
• ii. exceeds 90% theoretical density, go to step j;
• j. adding to said melt a predetermined amount of at least one material selected from the group consisting of magnesium and zinc;
• k. degassing said melt with a nonreactive gas;
• l. fluxing said melt with an alkaline based flux to remove dissolved gases and undesirable solids;
• m. testing theoretical density of said melt, and if the theoretical density:
• i. does not exceed 90% theoretical density, repeat steps k, l and m;
• ii. exceeds 90% theoretical density, go to step n;
• and
• n. transferring said melt into a casting mold to form a cast alloy comprising:
• aluminum, up to about 12 weight percent magnesium, up to about 7 weight percent zinc, and from about 5 to about 30 weight percent of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said cast alloy having a strengthening Al11X3 intermetallic phase in an amount in the range of from about 5 to about 30 weight percent, wherein X is at least one material selected from the group consisting of cerium, lanthanum, and mischmetal, said Al11X3 intermetallic phase having a microstructure comprising at least one morphological feature selected from the group consisting of lath features and rod features, said features having an average thickness of no more than 700 um and an average lath spacing of no more than 10 um, said microstructure further comprising an eutectic microconstituent that comprises more than about 10 volume percent of said microstructure.