非均匀固体热导率分布的重建:利用光声技术研究激光冲击的铝合金  

Reconstruction of thermal conductivity distribution of inhomogeneous solids: laser-hardened Al alloys studied by photoacoustic technique

作　　者：赵雁竹[1] 张淑仪[1] 张永康[2] 

机构地区：[1]南京大学声学研究所近代声学国家重点实验室,南京210093 [2]江苏理工大学材料工程系,镇江212013

出　　处：《声学学报》2002年第1期7-12,共6页Acta Acustica

摘　　要：利用光声检测技术，详细研究了由强激光脉冲冲击硬化的铝合金样品（２０２４－Ｔ６２）。在不同调制频率的激光照射下，利用光声技术测定样品表面温度的变化，并运用由脉冲谱技术和正则化算法导出的热波反演算法重建其热导率的深度分布。对不同冲击次数的硬化效果进行了分析，分析结果与利用显微维氏硬度计破坏性的测试所得的结果完全一致。说明这种光声实验系统和反演算法对于非均匀介质的深度剖面分析是一种无损地评价材料特性十分有效的方法。Photoacoustic measurement techniques can be used to determine thermal properties on and below the sample's surface, thus subsurface thermal inhomogeneities, such as continuous profiles of thermal parameters, become to be measurable by photoacoustic methods. In this paper, the study is focused on the quantitative characterization of material modifications in subsurface layers of laser-hardened Al alloy samples. The variation of surface temperature is measured by PA technique. Then a new numerical algorithm, carried out by employing the pulsed spectrum technique and the regularization method, is used to reconstruct thermal conductivity depth profiles. The experiment results are compared with those of Vickers microhardness depth profiles obtained by destructive method. It is demonstrated that there exists a close anticorrelation between microstructure depending hardness and local thermal conductivity. The presented results show the experiment and the algorithm is very effective for microstructure depth profile reconstruction by nondestructive method.

关 键 词：光声检测 铝合金 激光冲击 非均匀固体 热导率 表面温度 硬化效果 

分 类 号：O551.3[理学—热学与物质分子运动论]