Tailored nanoindentation experiments were used to determine the strain rate dependence of the hardness of AlN doped SiC produced by spark plasma sintering. It is shown that in the nanoindentation regime, where cracking is limited, the hardness of SiC reduces by 0·8 GPa/decade reduction in strain rate. This measured variation in hardness is consistent with estimates for the strain rate dependence of the lattice resistance (Peierls stress) of SiC. These experiments therefore open up the possibility to determine real constitutive equations for plasticity in SiC and other armour ceramics.
SwabJ.: ‘Recommendations for determining the hardness of armor ceramics’, Int. J. Appl. Ceram. Technol, 2004, 1, (3), 219–225.
2.
MarshD. M.: ‘Plastic flow in glass’, Proc. R. Soc. A, 1963, 279A, 420–435.
3.
SuzukiK., BeninoY., FujiwaraT. and KomatsuT.: ‘Densification energy during nanoindentation of silica glass’, J. Am. Ceram. Soc., 2002, 85, (12), 3102–3104.
4.
GerkA. P. and TaborD.: ‘Indentation hardness and semiconduc-tormetal transition of germanium and silicon’, Nature, 1978, 271, 732–733.
5.
VandeperreL. J., GiulianiF., LloydS. J. and CleggW. J.: ‘The hardness of silicon and germanium’, Acta Mater., 2007, 55, (18), 6307–6315.
6.
WeppelmanE. R., FieldJ. S. and SwainM. V.: ‘Observation, analysis, and simulation of the hysteresis of silicon using ultra-micro-indentation with spherical indenters’, J. Mater. Res., 1993, 8, (4), 830–840.
7.
BradbyJ. E., WilliamsJ. S., Wong-LeungJ., KucheyevS. O., SwainM. V. and MunroeP.: ‘Spherical indentation of compound semiconductors’, Philos. Mag. A, 2002, 82A, (10), 1931–1939.
8.
NieszD. E. and McCauleyJ. W.: ‘Advanced metals and ceramics for armor and anti-armor applications high-fidelity design and processing of advanced armor ceramics’, ARL-CR-594, Army Research Laboratory, Adelphi, MD, USA, 2007.
9.
TaborD.: ‘The physical meaning of indentation and scratch tests’, Br. J. Appl. Phys., 1956, 7, 159–166.
10.
ChengY. T. and ChengC. M.: ‘What is indentation hardness?’, Surf Coat. Technol, 2000, 133–134, 417–424.
11.
ChengY. T. and ChengC. M.: ‘Can stress—strain relationships be obtained from indentation curves using conical and pyramidal indenters’, J. Mater. Res., 1999, 14, (9), 3493–3496.
12.
HillR., LeeE. H. and TupperS. J.: ‘The theory of wedge indentation of ductile materials’, Proc. R Soc. A, 1947, 188A, 273–289.
13.
DugdaleD. S.: ‘Wedge indentation experiments with worked metals’, J. Mech. Phys. Solids, 1953, 2, 14–26.
14.
HirstW. and HowseG. J. W.: ‘The indentation of materials by wedges’, Proc. R Soc. A, 1969, 311A, 429–444.
15.
TaborD.: ‘Hardness of metals’;1951, Oxford, Clarendon Press.
16.
AtkinsA. G. and TaborD.: ‘Plastic indentation in metals with cones’, J. Mech. Phys. Solids, 1965, 13, 149–164.
17.
ChengY. T. and LiZ.: ‘Hardness obtained from conical indenters with various cone angles’, J. Mater. Res., 2000, 15, (12), 2830–2835.
18.
VandeperreL. J., GiulianiF. and CleggW. J.: ‘Effect of elastic surface deformation on the relation between hardness and yield strength’, J. Mater. Res., 2004, 19, (12), 3704–3714.
19.
WarrenP. D.: ‘Fracture of brittle materials: effects of test method and threshold stress on the Weibull modulus’, J. Eur. Ceram. Soc., 2001, 21, (3), 335–342.
20.
BasuS., MosesonA. and BarsoumM. W.: ‘On the determination of spherical nanoindentation stress—strain curves’, J. Mater. Res., 2006, 21, (10), 2628–2637.
21.
Fischer-CrippsA. C.: ‘Elastic—plastic behaviour in materials loaded with a spherical indenter’, J. Mater. ScL, 1997, 32, 727–736.
22.
TweedieC. A. and van VlietK. J.: ‘Contact creep compliance of viscoelastic materials via nanoindentation’, J. Mater. Res., 2006, 21, (6), 1576–1589.
23.
OyenM. L. and CookR. F.: ‘Load—displacement behavior during sharp indentation of viscous-elastic—plastic materials’, J. Mater. Res., 2003, 18, (1), 139–150.
24.
ChiangS. S., MarshallD. B. and EvansA. G.: ‘The response of solids to elastic/plastic indentation. II. Fracture initiation’, J. Appl. Phys., 1982, 53, (1), 312–317.
25.
LawnB. R. and MarshallD. B.: ‘Hardness, toughness, and brittleness: an indentation analysis’, J. Am. Ceram. Soc., 1979, 62, (7-8), 347–350.
26.
ChantikulP., AnstisG. R., LawnB. R. and MarshallD. B.: ‘A critical evaluated of indentation techniques for measuring fracture toughness. II. Strength method’, J. Am. Ceram. Soc., 1981, 64, (9), 539–543.
27.
CookR. F. and PharrG. M.: ‘Direct observation and analysis of indentation cracking in glasses and ceramics’, J. Am. Ceram. Soc., 1990, 73, (4), 787–817.
28.
GrauP., BergG., MeinhardH. and MoschS.: ‘Strain rate dependence of the hardness of glass and Meyer's law’, J. Am. Ceram. Soc., 1998, 81, (6), 1557–1564.
29.
KeulenN. M.: ‘Indentation creep of hydrated soda-lime silicate glass determined by nanoindentation’, J. Am. Ceram. Soc., 1993, 76, (4), 1904–1912.
30.
NganA. H. W., PethicaJ. B. and NgH. P.: ‘Strain-rate sensitivity of hardness of nanocrystalline Ni75at.%A125at.% alloy film’, J. Mater. Res., 2003, 18, (2), 382–386.
31.
GolovinY. I., IuninY. L. and TyurinA. I.: ‘Strain-rate sensitivity of the hardness of crystalline materials under dynamic nanoinden-tation’, DokL Phys., 2003, 48, (9), 505–508.
32.
Ur-RehmanN., BrownP. and VandeperreL. J.: ‘Evolution of the AIN distribution during sintering of AIN doped SiC’, Proc. 34th Conf. on ‘Advanced ceramics and composites’, Daytona Beach, FL, USA, January2010, The American Ceramic Society.
33.
OliverW. C. and PharrG. M.: ‘An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments’, J. Mater. Res., 1992, 7, (6), 1564–1583.
34.
SneddonI. N.: ‘Boussinesq's problem for a rigid cone’, Proc. Cambridge Philos. Soc., 1948, 44, 492–507.
35.
LandoltH. and BornsteinR.: ‘Elektrische, Piezoelektrische, Pyroelektrische, Piezooptische, Elektrooptische Konstanten und Nichtlineare Dielektrische Suszeptibilitaten’;1979, Berlin, Springer-Verlag.
36.
RayD., FlindersR. M., AndersonA. and CutlerR. A.: ‘Effect of room-temperature hardness and toughness on the ballistic perfor-mance of SiC-based ceramics’, Ceram. Eng. Set Proc., 2006, 26, (7), 131–142.
37.
FlindersM., RayD., AndersonA. and CutlerR. A.: ‘High-toughness silicon carbide as armour’, J. Am. Ceram. Soc., 2005, 88, (8), 2217–2226.
38.
FujitaS., MaedaK. and HyodoS.: ‘Dislocation glide motion in 6H SiC single crystals subjected to high-temperature deformation’, Philos. Mag. A, 1987, 55A, (2), 203–215.
39.
PirouzP., DemenetJ. L. and HongM. H.: ‘On transition temperatures in the plasticity and fracture of semiconductors’, Philos. Mag. A, 2001, 81A, (5), 1207–1227.
40.
PitchfordJ. E.: ‘Effects of structure on mechanisms of high temperature plastic deformation in oxide ceramics’, PhD thesis, University of Cambridge, Cambridge, UK, 1999.
41.
OhsawaK., KoizumiH., KirchnerH. O. K. and SuzukiT.: ‘The critical stress in a discrete Peierls—Nabarro model’, Philos. Mag. A, 1994, 69A, (1), 171–181.
42.
PeierlsR.: ‘The size of a dislocation’, Proc. Phys. Soc., 1940, 52, 34–37.
43.
CleggW. J., VandeperreL. J. and PitchfordJ. E.: ‘Energy changes and the lattice resistance’, Key Eng. Mater., 2006, 317–318, 271–276.
44.
AlexanderH. and HaasenP.: ‘Dislocations and plastic flow in the diamond structure’, Solid State Phys., 1968, 22, 27–158.
