Effects Of Composition And Heat Treatment On High Temperature Strength Of Arc Melted Tungsten Hafnium Carbon Alloys

The mechanical properties of rod and sheet fabricated from arc melted W-4Re-Hf-C alloys containing up to about 0.8 mol percent hafnium carbide (HfC) were evaluated in the as-worked condition. The DBTT's of electropolished bend and tensile specimens were independent of HfC content in this range but dependent on excess Hf or C above that required for stoichiometric HfC. Low temperature ductility was a maximum at Hf contents slightly in excess of stoichiometric. Variations in high temperature strength were also dependent on excess Hf and C. Maximum creep strengthening also occurred at Hf contents in excess of stoichiometric. Analysis of extracted second phase particles indicated that creep strength was reduced by increasing WC content in the HfC particles.

A study was made of the thermochemical processing of a series of Mo-Hf-C alloys. The processes either produced an overaged carbide precipitate within a strain hardened matrix or allowed the formation of a finer precipitate during fabrication by a dynamic strain aging reaction. The short time tensile properties of the strain aged alloys were superior to those of any other molybdenum alloy studied to date.

Contains more than 1400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric units, and many also include U.S. customary units