BrandonBerchtold said:
If there is no such series (perhaps due to error bars being too large to generalize the properties for certain materials), then what do mechanical engineers use as their reference for deciding which specific alloys to use for certain niche applications?
jrmichler said:
It's the ASM Metals Handbook:
I'm involved in such an exercise regarding certain alloys, and I what I've found is that there is no comprehensive reference for a given alloy. In general, engineering/manufacturing companies rely on their own proprietary material and product specifications, which are based on proprietary mechanical testing.
Books like ASM Handbooks use published, non-proprietary data (which might originate in universities (academia), manufacturers, or government lab), unless the contributor is allowed to access proprietary data. In addition, one must realize that in general, for metals/alloys, they are generally in the annealed state, and one has to determined the work hardening curve and select a narrow range of application.
National research facilities may perform mechanical tests and provide them for national programs. For example, there are material property handbooks for materials used in nuclear reactors and for nuclear fuel. In the US, the Atomic Energy Commission (AEC) and it's successor Dept of Energy (DOE) published a materials property (MATRPO) dataset for materials used in Light Water Reactors (fuel rods, fuel assemblies and control elements). However, manufacturers (B&W, CE, Exxon/ANF, GE, Westinghouse) have their own proprietary databases. MATPRO is used by the NRC and DOE, and by academia, and independent manufacturers/designers. One must realize that the mechanical properties of an alloy are affected not only by composition, but by the alloy's microstructure (e.g., grain size, texture, dislocation density, . . . ), which is dependent on the manufacturing process. Another reason for using one's proprietary material properties is that one must assure and certify that the material conforms to proprietary standards and there are legal liabilities to which the organization is subject.
Prior to MATPRO, Battelle Memorial Institute published a set of books of material properties (thermophysical and thermomechanical) of fuel materials and structural alloys, but they covered so many basic materials, that they were far from comprehensive in a given metal or alloy, i.e., they reported what was available, and in looking at the data, there is considerable scatter.
For fast reactors, there is the Nuclear System Materials Handbook, which provides both thermophysical and thermomechanial properties. The mechanical properties were determined from testing performed by the Hanford Engineering Development Laboratory (HEDL). For a given alloy, e.g., 304 or 316 stainless steel, HEDL developed restrictive alloy compositions and imposed a restricted manufacturing route in order to limit the scatter in the results. With respect to the select stainless steel grades, property data are provided for annealed and cold-worked materials. HEDL did a comprehensive program of testing strength of certain alloys as a function of composition and cold work levels, and mechanical testing from room temperature to ~816°C (1500°F) and a range of strain rates (10
-5 to 10
2 s
-1).
For fusion systems, there is the ITER Materials Handbook, to which various national laboratories and industrial organizations contribute.
The National Bureau of Standards (NBS), now National Institute of Standards and Technology used to provide material properties, usually thermophysical rather than thermomechanical, but they do less of that now.
For boilers and pressure vessels, ASME has the Boiler and Pressure Vessel Code, which provides selected material properties, and may reference standards from other organizations like ASTM. Unless specified one must assume the alloy is in the annealed state.
In aerospace, there is the Aerospace Structural Metals Handbook sponsored by the Directorate of Materials and Processes, Aeronautical Systems Division, Air Force Command, Wright Patterson Air Force Base, Ohio and published by various universities, primarily Syracuse University in the beginning. They have separate volumes for Ferrous and Nonferrous Alloys. Now there is the Aerospace Structural Metals Database (ASMD) published by CINDAS LLC, Purdue Technology Center- Aerospace, 1801 Newman Road, Suite 1150, West Lafayette, IN 47906-4524.
I have used all of the above databases, and in some cases found errors, inconsistencies and discrepancies. In addition, I've used the literature on specific properties of specific alloys, and I find considerable scatter. In the case of a single alloy, 316 (UNS 31600), all 316 is not the same, i.e., there is some heat-to-heat variability, and within a given heat, there is variability in the intermediate and final product.
I'm currently involved in program looking at high strength stainless steels, and I will be recommending a comprehensive testing program to determine thermophysical, thermomechanical, and behavioral/chemical properties (and models). Behavioral properties include corrosion, certain chemical interactions, and radiation effects on the alloy microstructure, and how thermophysical and thermomechanical properties change with those effects.
One's testing program must consider the alloy, manufacturing (product) variability and performance in the intended environment. In nuclear and aerospace programs, one will have to determine properties up to and including melting, and for some hypothetical situations, beyond melting, and in a program like ITER, one might need material properties at cryogenic temperatures, e.g., down liquid He temperature.