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Strengthening of Alkali Halides by Divalent‐Ion Additions
Author(s) -
CHIN G. Y.,
UITERT L. G.,
GREEN M. L.,
ZYDZIK G. J.,
KOMETANI T. Y.
Publication year - 1973
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1973.tb12688.x
Subject(s) - knoop hardness test , halide , divalent , alkali metal , dopant , chemistry , yield (engineering) , indentation , inorganic chemistry , ion , analytical chemistry (journal) , crystallography , mineralogy , indentation hardness , materials science , composite material , doping , microstructure , organic chemistry , optoelectronics
Single crystals of NaCl, NaBr, KCl, and KBr containing divalent additions of Ca 2+ , Sr 2+ , and Ba 2+ were tested mechanically. In the solution‐treated condition, the yield strength, σ v , as determined from compression testing in a 〈100〉 direction is essentially dependent on the concentration of the dopant only and is independent of the species of either the dopant or of the host material. All crystals soften on aging, with the exception of the NaCl:Ca 2+ , NaBr:Ca 2+ , and NaBr:Sr 2+ systems. In addition, correlation was good between σ v , and the Knoop hardness number, H , obtained by indentation with the long axis of the indenter aligned in 〈100〉. The equation is of the form σ v = C ( H–H 0 ), where C ≅ 0.21 for all four halide families and H 0 is near the hardness value of the pure halides. Furthermore, H 0 ≅5×10 −3 E 111 , the Young's modulus in the 〈111〉 direction. Hence σ v ≅0.21 H –10 −3 E 111 .