标题：A study on fracture toughness of potassium dihydrogen phosphate single crystals
作者：Huang, Pingping; Ding, Jianxu; Wang, Duanliang; Liu, Hui; Xu, Longyun; Li, Xianglin; Wang, Bo; Liu, Guangxia; Wang, Shenglai
作者机构：[Huang, Pingping; Liu, Hui; Xu, Longyun; Li, Xianglin; Wang, Bo; Wang, Shenglai] Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Shandong, Peo 更多
通讯作者：Wang, Shenglai;Wang, SL;Wang, SL
通讯作者地址：[Wang, SL]Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Shandong, Peoples R China;[Wang, SL]Shandong Univ, Key Lab Funct Crystal Mat & Devic 更多
摘要：The cracking of KDP crystals during the growth & fabrication process is a serious problem that limits their application in the large-aperture high-power laser system; furthermore, the cracking is mainly attributed to their high brittleness. In order to explore the mechanical parameters related to KDP crystal cracking in detail, we measured the fracture toughness of KDP crystals as a function of temperature using the single-edge notched beam (SENB) method up to 170 degrees C. Meanwhile, the effects of crystallographic orientation, annealing and loading rate on the fracture toughness values were investigated in detail. Strong orientation dependence was observed on the fracture toughness of KDP crystals, and the relationship was concluded as follows: x-cut > type II > type I > z-cut. With the increase in temperature, the fracture toughness of crystals increased and reached its maximum value at 160 degrees C; then, it decreased, indicating that 160 degrees C is the temperature at which brittle-to-ductile transition occurs. Using an optical microscope, it was observed that the fractured surfaces of the samples become gradually rough with the increase in temperature. This may offer a viewpoint for understanding the dependence of fracture toughness on temperature. Furthermore, annealing and decrease in the loading rate were conducive to the significant increase in the fracture toughness of KDP crystals.