中文摘要：

此文用密度泛函理论的赝势平面波方法的第一性原理研究了过渡金属化合物ZrB3与NbBs（m—AlB2、OsB3和MoB3结构）在高压下的力学性质和电子结构特点，获得了在常压下，m—A1Bz是最稳定的结构，当压强升高到40GPa时发生相变，高压下最稳定是OsB3结构．m—A1Bz—NbBs具有最大的剪切模量204GPa，最高的德拜温度921K和最大的硬度值27．3GPa，属于潜在的超不可压缩材料．MoB3-NbB3、OsB3-NbB3和m—A182-ZrB3的硬度值分别达到了24．9GPa、22．6GPa和19．8GPa．它们的电子态主要是由M-4d态和B-2p态杂化叠加形成的，在费米能级处取值均不为零，故这些化合物都具有金属性等有益结果．

英文摘要：

The mechanical properties and the electronic structures of transition metal compounds ZrB3 and NbB3 （m-AlB2, OsB3and MoB3 structures） under high-pressure are studied by using the first-princi- ples within density {unctional theory. It was found that m-AlB2 is the most stable structure under nor- mal pressure. The pressure- induced phase transition occurs at the pressure of 40 GPa, OsB3 structure becomes the most stable one under high pressure, m-A1B2-NbB3 has a maximum shear modulus of 204 GPa, the highest Debye temperature of 921 K, and the highest hardness of 27.3 GPa. The hardnesses are estimated to be 24.9 GPa, 22.6 GPa and 19.8 GPa for MoB3-NbB3, OsB3-NbB3and m-A1B2-ZrB3, respectively. The calculated density of states （DOS） illustrated that the electronic structures of consid- ered compounds are governed by the strong hybridization between M-4d and B-2p states. All compounds are metallic.