Abstract: Processes for high speed machining of workpiece materials using high performance tools with prolonged tool life and improved surface finish are provided by vibrating the tool and/or the workpiece at a frequency greater than the frequency of shear localization in the primary shear zone or chip segmentation occurring in the absence of tool vibration, with an amplitude sufficient to break up the tool-chip atomic contact, thereby decreasing the tool-chip contact length through decreasing the tool-chip contact time, thereby suppressing accelerated chemical tool wear caused by dissolution of the tool into the workpiece by nanocrystalline grain boundary diffusion and grain boundary sliding mechanisms by preventing shear localization associated with nanocrystalline grain formation in the primary shear zone of the chip, and suppressing oxidation wear of the tool by preventing segmentation of the chip.

Abstract: Processes for high speed machining of workpiece materials using high performance tools with prolonged tool life and improved surface finish are provided by vibrating the tool and/or the workpiece at a frequency greater than the frequency of shear localization in the primary shear zone or chip segmentation occurring in the absence of tool vibration, with an amplitude sufficient to break up the tool-chip atomic contact, thereby decreasing the tool-chip contact length through decreasing the tool-chip contact time, thereby suppressing accelerated chemical tool wear caused by dissolution of the tool into the workpiece by nanocrystalline grain boundary diffusion and grain boundary sliding mechanisms by preventing shear localization associated with nanocrystalline grain formation in the primary shear zone of the chip, and suppressing oxidation wear of the tool by preventing segmentation of the chip.

Abstract: Processes for high speed machining of workpiece materials using high performance tools with prolonged tool life and improved surface finish are provided by vibrating the tool and/or the workpiece at a frequency greater than the frequency of shear localization in the primary shear zone or chip segmentation occurring in the absence of tool vibration, with an amplitude sufficient to break up the tool-chip atomic contact, thereby decreasing the tool-chip contact length through decreasing the tool-chip contact time, thereby suppressing accelerated chemical tool wear caused by dissolution of the tool into the workpiece by nanocrystalline grain boundary diffusion and grain boundary sliding mechanisms by preventing shear localization associated with nanocrystalline grain formation in the primary shear zone of the chip, and suppressing oxidation wear of the tool by preventing segmentation of the chip.

Abstract: Processes for high speed machining of workpiece materials using high performance tools with prolonged tool life and improved surface finish are provided by vibrating the tool and/or the workpiece at a frequency greater than the frequency of shear localization in the primary shear zone or chip segmentation occurring in the absence of tool vibration, with an amplitude sufficient to break up the tool-chip atomic contact, thereby decreasing the tool-chip contact length through decreasing the tool-chip contact time, thereby suppressing accelerated chemical tool wear caused by dissolution of the tool into the workpiece by nanocrystalline grain boundary diffusion and grain boundary sliding mechanisms by preventing shear localization associated with nanocrystalline grain formation in the primary shear zone of the chip, and suppressing oxidation wear of the tool by preventing segmentation of the chip.

Abstract: Processes for producing gray cast iron and the resulting gray cast iron exhibiting consistently good surface finish with prolonged tool life during finish machining with cubic boron nitride and silicon nitride cutting tools at high cutting speeds and low feed rates are provided comprising (1) adding microalloying elements with strong affinity for nitrogen to a gray iron melt; (2) adding microalloying elements with strong affinity for carbon to said melt; and (3) adding microalloying elements with strong affinity for oxygen to said melt, to form a chemically stable, high melting or refractory oxide protective layer at the cutting edge of the tool during metal cutting, thereby suppressing chemical wear.

Abstract: Processes for producing gray cast iron and the resulting gray cast iron exhibiting consistently good surface finish with prolonged tool life during finish machining with cubic boron nitride and silicon nitride cutting tools at high cutting speeds and low feed rates are provided comprising (1) adding microalloying elements with strong affinity for nitrogen to a gray iron melt; (2) adding microalloying elements with strong affinity for carbon to said melt; and (3) adding microalloying elements with strong affinity for oxygen to said melt, to form a chemically stable, high melting or refractory oxide protective layer at the cutting edge of the tool during metal cutting, thereby suppressing chemical wear.

Abstract: Processes for producing gray cast iron and the resulting gray cast iron exhibiting consistently good surface finish with prolonged tool life during finish machining with cubic boron nitride and silicon nitride cutting tools at high cutting speeds and low feed rates are provided comprising (1) adding microalloying elements with strong affinity for nitrogen to a gray iron melt; (2) adding microalloying elements with strong affinity for carbon to said melt; and (3) adding microalloying elements with strong affinity for oxygen to said melt, to form a chemically stable, high melting or refractory oxide protective layer at the cutting edge of the tool during metal cutting, thereby suppressing chemical wear.

Abstract: A turbine airfoil includes a plurality of internal ribs defining at least two independent serpentine cooling circuits arranged in part in different longitudinal tiers, with an outer tier circuit being disposed in part longitudinally above an inner tier circuit for differentially longitudinally cooling the airfoil.

Abstract: A process for producing compacted graphite cast iron thin walled shaped castings in a high productivity line is provided which comprises: (i) forming a near eutectic melt of cast iron, having a low sulfur content, preferably around 0.01% by weight; (ii) adding to the melt sufficient graphite stabilizing agents such as silicon to suppress the carbide eutectic formation at the large undercooling characteristic of thinner sections of the castings; (iii) admixing at least one rare earth containing additive with said melt to form rare earth compounds so as to reduce and maintain the Henrian oxygen activity in the melt at about 10.sup.-6 ; (iv) inoculating the melt in an optimum manner to promote the required degree of interconnected vermicular graphite growth, and (v) casting the resulting melt.

Abstract: Process for producing vermicular cast iron comprising: (i) forming a near eutectic melt having a sulfur content preferably less than about 0.025% by weight; (ii) admixing at least one rare earth-containing additive with said melt to form stable rare earth oxysulfides thereby reducing and maintaining the Henrian sulfur activity in the melt at between about 0.004 and 0.035; and (iii) thereafter, allowing said melt to solidify.