In connection with creep studies of graph ite, t he need a rose for accu rate ther mal expansion data on the three grades of graphite being investigated. Therefore, the linear thermal expansion of specimen s of the t hree grades, cut in t hree direction s with respect to the direction of extrusion or of molding press ure, was determ in ed at various t e mperatures between 20° and 1,370° C in vacuum. Resul ts show that specime ns cut perpendicular to the extrusion direction or paralJel to the direction of molding pressLil e had greater expan sion s than specimen s cut parall el to t he extrusion d irection or p erpendicular to the molding pressure. The data obtain ed are tabulate d.

The principal purpose of this investigation was to determine the creep behavior and strength at 1200" to 1850'F. of cermets which may be used in the high-temperature areas of aircraft. Initially a series of bending tests was made on variations of Kennametal 150-type Kentanium containing from 5 to 3oy0 nickel binder. The 5, 15, and 20% compositions were the strongest and the most creep resistant. Because of the need for both thermal and mechanical shock resistance, tensile creep tests were then made on K15O-type Kentanium compositions containing 20, 25, and 30% nickel binder. A limited number of tests also were made on Kennametal composition K162B and on Firth Sterling composition FS-27. The cermet K162B was the most creep resistant and the strongest. Linear thermal expansion determinations were made on Kennametal compositions K138A, K138, K151, and K151A. Their coefficients of expansion between room temperature and 1205°C. ranged from 8.1 X 10-6to 8.6 X per "C. Metallographic examinations were made of all the tensile-tested specimens ; in general, the test strains were too small to cause any noticeable deformation or changes in microstructure.