12231 ASTM Standards for Advanced Materials

The work of the task groups of the subcommittees may be either ad hoc or may follow a program of work. Because the standardization process of ASTM is voluntary, the work is accomplished only if willing volunteers [i.e., someone with an interest (technical, industrial, or profit)] are able to "champion" a standard through the full-consensus approval process. ASTM has six different types of standards that require this level of approval: test method (procedures for determining material properties or product performance), specification (concise statement of the requirements that need to be satisfied), terminology (definitions, nomenclature, symbols, initialisms, and acronyms), guide [options and instructions (e.g., other ASTM test methods) but does not require or recommend a specific course of action], and classifications (systematic arrangement or division of materials or products into groups). Table 12.1 provides a partial listing of those ASTM

TABLE 12.1 ASTM Committees on Advanced Materials

Committee

B-10 Reactive and Refractory Metals and Alloys

C-5 Manufactured Carbon and Graphite Products

C-21 Ceramic Whitewares and Related

Products C-28 Advanced Ceramics

D-30 Composite Materials F-1 Electronics

F-4 Medical and Surgical Materials and Devices

Materials

Titanium

Carbon, graphite, carbon-carbon composites Porcelains, aluminum oxide products

Monolithic and composite technical ceramics

Polymer and metal matrix composites Electronic substrates, circuit boards, etc. Biomaterials committees (out of over 150 total committees) working on advanced materials as an obvious part of the committee charter. Other committees may also develop standards for advanced materials indirectly through other related work.

Not all advanced materials are represented by the committees of ASTM shown in Table 12.1. This does not mean standards for those missing advanced materials are not or will not be developed in the United States. It simply means that the "critical mass" of people and interest has not yet developed for a committee to be formed within ASTM on that topic. ASTM standards can be easily assessed via the Annual Book of ASTM Standards (either hard-copy form in printed books or in electronic form on compact disk) [6] or through the World Wide Web through ASTM's web page [7].

An example of problems addressed for elevated temperature of a particular advanced material (ceramic matrix composite) is shown in Fig. 12.2 where the temperature distributions in a test specimen being held in hot, warm, and cold grips are illustrated. As used here, grips can be located outside the furnace and either water-cooled (cold grips) or noncooled [or heated] (warm grips). Grips can also be located inside the furnace and exposed to the test temperature (hot grips). Thermal analyses such as those shown in Fig. 12.2 have indicated substantial temperature gradients when using cold grips (AT«1200°CinAL«50 mm). Such steep temperature gradients may introduce thermal stresses and thereby promote nongage section failures. Progressively less steep temperature gradients exist for warm and hot grips.

A failure outside the gage section, which would be considered unacceptable according to the criteria in current ASTM standards (e.g., C1275-95 [8] on tensile tests of CFCCs at room temperature), could be common for a material that

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