激光功率对激光粉末床熔融成形Al_(2)O_(3)-ZrO_(2)共晶陶瓷熔池形态、微观组织和力学性能影响的研究  

Effects of Laser Power on Molten Pool Morphology,Microstructure,and Mechanical Properties of Al_(2)O_(3)-ZrO_(2) Eutectic Ceramics Shaped by Laser Powder Bed Fusion

作　　者：熊志伟 张凯[1] 刘婷婷[1] 廖文和[1] Xiong Zhiwei;Zhang Kai;Liu Tingting;Liao Wenhe(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094

出　　处：《中国激光》2024年第10期231-243,共13页Chinese Journal of Lasers

基　　金：国家自然科学基金(52005262)。

摘　　要：熔融生长的Al_(2)O_(3)-ZrO_(2)共晶陶瓷具有优异的高温性能。采用激光粉末床熔融(LPBF)直接制备Al_(2)O_(3)-ZrO_(2)共晶陶瓷,研究了不同激光功率下的单道形貌特征及块体表面质量、物相组成、微观组织结构的演变规律和力学性能。结果表明,激光功率的提升将增加熔池的长度和单沉积道的宽度。Al_(2)O_(3)-ZrO_(2)共晶陶瓷的表面粗糙度(Ra)和气孔率均随着激光功率的增加先降低后升高。在没有添加Y2O_(3)等稳定剂的条件下,Al_(2)O_(3)-ZrO_(2)共晶陶瓷的物相主要包括α-Al_(2)O_(3)、m-ZrO_(2)和亚稳相t-ZrO_(2)。随着激光功率的增加,m-ZrO_(2)逐渐减少,这是由于LPBF的快速冷却过程抑制了马氏体相变。样件的晶粒尺寸随着激光功率的增加呈增大趋势,晶界密度减小,因此测量的显微硬度和断裂韧性呈现下降的趋势。当激光功率为60 W时,得到硬度为Hv=17.19 GPa和断裂韧性为KIC=6.67 MPa·m1/2的最优力学性能样品。Objective Moltengrown Al_(2)O_(3)-ZrO_(2) eutectic ceramics exhibit outstanding hightemperature performance and have potential technological applications in aviation,aerospace,and nuclear engineering.Laser powder bed fusion(LPBF)technology has several advantages,including high design flexibility,low production costs,and short delivery cycles,making it promising in the direct manufacture of complex Al_(2)O_(3)-ZrO_(2) eutectic ceramic components with dense microstructures.However,the transient interaction between ceramic powder and lasers still requires clarification,and insufficient ceramic toughness poses significant challenges to the direct fabrication of ceramics via LPBF.Consequently,it is imperative to investigate the realtime morphology evolution of molten pools and establish a correlation among the“material process microstructure mechanical properties”to lay the groundwork for producing highperformance ceramic materials.This paper presents an innovative study based on realtime highspeed imaging systems and threedimensional confocal microscope reconstruction of surface information in single deposition tracks.Morphological characteristics such as molten pool length and single deposition track width are statistically analyzed.The results indicate that increasing laser power leads to longer molten pools and wider single deposition tracks.To improve the correlation among the material process microstructure mechanical properties of Al_(2)O_(3)-ZrO_(2) eutectic ceramics,characterization and testing methods,including Xray diffractometer(XRD),scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and microhardness measurements,are employed to investigate the surface quality,relative density,phase composition,microstructure,and mechanical property evolution of LPBFproduced Al_(2)O_(3)-ZrO_(2) eutectic ceramics under different laser powers.The findings demonstrate a gradual reduction in mZrO_(2) with increasing laser power owing to the inhibition of the martensitic phase transformation during rapid

关 键 词：激光技术 激光粉末床熔融 Al_(2)O_(3)-ZrO_(2)共晶陶瓷 熔池 晶粒尺寸 断裂韧性 

分 类 号：TH16[机械工程—机械制造及自动化] TP277[自动化与计算机技术—检测技术与自动化装置]