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The microstructure，tensile and damage tolerance properties in different directions of Al-Mg-Sc-Zr alloy fabricated through selective laser melting（SLM）have been investigated. The results show that the YZ plane is a bimodal grain morphology composed of fine equiaxed grains and coarse columnar grains，while the XY plane is composed of fine equiaxed grains. The yield strength and tensile strength in both 0° and 90° directions are over 500 MPa，and the anisotropy is small，while the elongation in 90° direction is significantly lower than the 0° direction due to the lack of fusion（LOF）defects between the deposited layers. The KIC of the 0° and 90° CT samples are respectively 21.41 MPa·m1/2 and 20.89 MPa·m1/2. The resistance to crack propagation in columnar grains region is lower and leading to a smaller KIC for 90° CT samples. The microstructure and defects are the two main factors that affect the anisotropy of crack propagation performance. The LOF defects play a leading role in the near-threshold regime，and the crack propagation rate is faster when the crack propagation plane is parallel to transverse direction. On the other hand，the microstructure plays a leading role in the steady-state propagation regime. The fracture surface exhibits transgranular fracture when the crack propagation plane is parallel to transverse direction，which provides higher crack propagation resistance and result in lower crack propagation rate.

Abstract: The equilibrium internuclear separation, harmonic frequency, dissociation energy and potential energy curve (PEC) of the HBr(X1Σ+) molecule have been investigated by using the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the correlation-consistent quintuple basis set augmented with diffuse functions, aug-cc-pV5Z, in the valence range. The PEC calculations cover the internuclear distance range from 0.08 to 2.08nm. The PEC is fitted to the analytic Murrell–Sorbie function, which is used to reproduce the spectroscopic parameters, such as ωeχe , αe , Be and D 0. The present D 0, De , Re , ωe , ωeχe , αe and Be are of 3.7665eV, 3.9289eV, 0.14195nm, 2642.68cm−1, 45.6118cm−1, 0.23525cm−1 and 8.40417cm−1, respectively, which almost perfectly conform to the available measurements. With the potential determined at the MRCI/aug-cc-pV5Z level of theory, the total of 20 vibrational states is predicted when the rotational quantum number J is set to equal zero (J =0) by numerically solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J =0 for the first time, which are in excellent agreement with the available experimental data. [Copyright &y& Elsevier]