Strength of coherently strained nanolayers under high temperature nanoindentation

K.M.Y. P'ng, X.D. Hou, D.J. Dunstan, A.J. Bushby

    Research output: Chapter in Book/Report/Conference proceedingConference proceedingpeer-review


    Semiconductor strained layer superlattices are an ideal model material to study the effects of coherency strain in plasticity, due to the fine control of nanolayer thickness and internal strain afforded by MBE deposition. Previously, nanoindentation of bulk InGaAs at 300K gave a yield pressure of 6GPa (Jayawera et al Proc. Roy Soc, A459, 2049, 2003) while bending at 500 centigrade gave a yield value of 30MPa (Pp’ ng et al Phil. Mag. 85, 4429, 2005). In contrast, coherently strained InGaAs superlattices gave nanoindentation values of 3GPa at room temperature and bending at 500oC gave a yield value also around 3GPa. It appears that the coherency strain can impart an athermal strengthening to the superlattice. It is clearly necessary to do mechanical testing over the range 300-800K that will be able to link the room temperature nanoindentation with the results from the high temperature bending experiment and to determine the relationship between strength, coherency strain and temperature. Preliminary experiments on these samples at elevated temperatures using a hot stage and the UMIS nanoindentation system is difficult but feasible with the help of AFM to verify the contact area.
    Original languageEnglish
    Title of host publicationMaterials Research Society Symposium Proceedings
    PublisherCurran Associates inc.
    Number of pages6
    ISBN (Print)9781604234251
    Publication statusPublished - 2006
    EventMaterials Research Society Symposium - Boston, Massachusetts, United States
    Duration: 27 Nov 20061 Dec 2006


    ConferenceMaterials Research Society Symposium
    Country/TerritoryUnited States
    CityBoston, Massachusetts


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