45号钢表面激光硬化拉伸力学性能与断口分形维数关系的研究（英文）  

Research of Relationship between Tensile Mechanical Properties of 45 Steel Laser-Hardened Surfaces and Fracture Fractal Dimension

作　　者：刘安中[1] 张速[1] 丁克伟[1] 雷声[2] 

机构地区：[1]安徽建筑大学土木工程学院,安徽合肥230601 [2]安徽建筑大学机械与电气工程学院,安徽合肥230601

出　　处：《激光与光电子学进展》2016年第1期137-142,共6页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(11472005)

摘　　要：采用激光相变硬化技术对45号钢拉伸试样表面进行处理,通过拉伸实验获得试样的强度极限,测量了硬化层深度和硬化表面硬度,并用电子显微镜(SEM)对断口表面进行了分形分析,断面具有分形特征,利用分形理论计算了断面的分形维数。研究结果表明,随着激光束功率的增大,试样表面硬化层的深度和硬度是增加的,导致拉伸强度极限逐渐降低,断面分形维数也随之增大。对于该种材料,拉伸强度极限与断口分形维数可以互相表征。In this study, 45 steel tensile specimens were hardened by laser during a surface experiment that used different laser power strengths, whereas the ultimate tensile strength of each specimen was obtained during a tensile experiment. These experiments measured the depth and hardness of the hardening layers of the surface areas and logged fracture photographs using a scanning electric microscope （SEM） to perform the fractal analysis. The fracture showed fractal characteristics; therefore, fractal theory was applied to calculate the fractal dimension of the fracture. The conclusive research results show that the sample surface-hardening layer depths and surface hardness can be increased by increasing the laser power, and thus causes the gradual decrease of the ultimate tensile strength and the increase of the fracture fractal dimension. The ultimate tensile strength and the fracture fractal dimension can be characterized for this material type.

关 键 词：激光硬化 力学性质 拉伸断口 分形维数 

分 类 号：TG161[金属学及工艺—热处理]