But the precondition of this method is that the material must be the elastic isotropy . for the elastic anisotropy , because of the difference in the each direction of mechanical properties , actually , the result of the nanoidentation load - displacement data is the synthesis of the mechanical properties in every direction 但是這種方法的一個(gè)前提是各向同性的材料,對(duì)于各向異性的材料,因?yàn)闄C(jī)械性質(zhì)在各個(gè)方向上不同,所以在一個(gè)方向上的壓痕試驗(yàn)結(jié)果實(shí)際上是各個(gè)方向不同材料性質(zhì)的一個(gè)綜合值。