| 释义 |
pre-precipiˈtation, a. Metallurgy.
[pre- B. 2.]
Applied to phenomena occurring at or immediately before the onset of precipitation from solid solution in alloys, esp. the separation of submicroscopic particles from which crystals later develop.
1936M. Cohen in Metals Technol. Oct. 14 (heading) Pre-precipitation behavior of the alloy. Ibid. 15 The resistance and dilation curves indicate knot formation even at 200°, although there is no pre-precipitation hardening at this temperature. 1949J. E. Garside Process & Physical Metall. xii. 213 This process of age⁓hardening consists of two stages—(i) Pre-precipitation stage resulting in the formation of nuclei; (ii) Growth of the nuclei, first into particles of ultramicroscopic size, and then of microscopic size. 1959B. Chalmers Physical Metall. viii. 391 The desirable results of precipitation are almost always obtained when a very large number of precipitate particles or pre-precipitation zones are formed. 1965Hunsicker & Stumpf in C. S. Smith Sorby Centennial Symposium Hist. Metall. xviii. 287 In the face of mounting evidence the conviction became widespread that some sort of ‘pre-precipitation’ structure was developed at low temperatures and possibly at higher temperatures prior to and preparatory to actual precipitation. |