超高应变率激光冲击不同厚度Al7050合金的层裂研究（英文）  

Spall of Al7050 Alloy with Different Thicknesses Under Ultrahigh Strain Rate Laser Shock Peening

作　　者：吴俊峰 邹世坤 车志刚 巩水利 曹子文 Wu Junfeng;Zou Shikun;Che Zhigang;Gong Shuili;Cao Ziwen(Science and Technology on Power Beam Processes Laboratory,AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]中国航空制造技术研究院高能束流加工技术重点实验室,北京100024

出　　处：《稀有金属材料与工程》2019年第4期1096-1101,共6页Rare Metal Materials and Engineering

基　　金：National Science and Technology Major Project of China(2016YFB1102705)

摘　　要：分析不同工艺参数(工艺1和工艺2)激光冲击不同厚度Al7050合金的层裂特性,研究Al7050合金的层裂机理和层裂阈值。采用光子多普勒测速(PDV)系统和扫描电镜(SEM),分析工艺1激光冲击0.33 mm厚Al7050合金的自由面质点速度和自由面层裂断口形貌。采用超声波无损检测、光学显微镜(OM)和扫描电镜(SEM),分析工艺2激光冲击5mm厚Al7050合金的层裂大小、层裂厚度和层裂断口形貌。研究结果表明,基于PDV测试数据,获得激光冲击0.33 mm厚Al7050合金的层裂强度和激光冲击应变率。0.33mm厚Al7050合金的自由面断口形貌被详细分析。随着连续激光冲击次数增加,5mm厚Al7050合金的层裂尺寸增加,层裂厚度范围为343μm到364μm。层裂机理为微空洞的韧性断裂和直裂纹的脆性断裂的混合断裂。单点连续5次激光冲击为5 mm厚Al7050合金的层裂阈值。与基体材料相比,单点连续5次激光冲击5mm厚Al7050合金的表层显微硬度提高,而自由面附近的显微硬度降低。研究结果不仅为激光冲击强化铝合金的层裂行为研究提供重要见解,而且为激光冲击强化工业应用避免层裂提供基础研究。The spall characteristics of Al7050 alloy with different thicknesses treated by laser shock peening(LSP) with different process parameters(Process-1 and Process-2) were investigated to obtain the spall mechanism and spall threshold. The particle velocity of rear free surface and spall crater morphology in 0.33 mm thick Al7050 induced by LSP with Process-1 were measured and analyzed by a Photonic Doppler Velocimetry(PDV) system and scanning electron microscope(SEM), respectively. Spall sizes, spall thicknesses and spall fracture morphology in 5 mm thick Al7050 induced by LSP with Process-2 were analyzed by C-scan ultrasonic nondestructive testing with water immersion, optical microscope(OM) and SEM, respectively. The spall strength and LSP strain rate of 0.33 mm thick Al7050 were calculated by PDV data. Spall crater morphology was also analyzed. Results show that the spall sizes of 5 mm thick Al7050 increase with continued multiple LSP impacts and its spall thicknesses are in the range from 343 μm to 364 μm. Spall mechanism is mixture ruptures of ductile behavior with spherical voids and brittle behavior with straight cracks. Continued LSP-5 was the spall threshold of 5 mm thick Al7050. Compared with as-received material, the micro-hardness of 5 mm thick Al7050 with continued LSP-5 increases in the surface layer and decreases near rear free surface. The results provide not only some important insights on the spall behavior of aluminum alloy with laser shock but also fundamental research for avoiding the spall in industrial applications.

关 键 词：Al7050合金 激光冲击强化 层裂机理 层裂阈值 层裂断口形貌 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]