高强度微波处理对落叶松木材力学性质的影响

Influence of Intensive Microwave Treatment on Mechanical Properties of Larch Wood

着重考查了经过高强度微波辐照后,落叶松木材冲击韧性和弯曲性能的变化。结果表明,适当的高强度微波辐照对落叶松木材的力学性能影响不大,弯曲弹性模量和冲击韧性下降不足10%;但是不当的处理条件能够显著降低木材的力学性能。有时高强度微波处理能够使落叶松木材的冲击韧性有所提高,这与木材内部的生长应力一定程度的释放有关。扫描电子显微镜观察显示,经高强度微波处理后落叶松木材的微观结构发生了一些变化,包括微细裂纹的形成、纹孔膜破裂等,这些微观结构变化有助于释放木材内部的生长应力,从而改善力学性能。

This paper focuses on the change of bending properties and toughness of larch wood after intensive microwave treatment. Results show that proper intensive microwave irradiation has little influence on the mechanical properties of larch wood, which results in no more than 10 percent decrease in modulus of elasticity and impact toughness of larch wood compared with the untreated wood. However, the mechanical properties of larch wood substantially reduce under improper microwave treatment. The impact toughness of larch wood can be improved in some microwave irradiation experiments, which is arisen from the release of growth stress of larch wood. After intensive microwave treatment, changes in microstructure of larch wood, such as the formation of tiny cracks in the cell wall and the pit membranes, were observed by scanning electronic microscope. The changes of these microstructures are in favor of releasing the growth stress for larch wood, thereby improve the mechanical properties.