تحسين خصائص سطح سبيكة الالمنيوم باستخدام الاكساء بالليزر بانابيب كاربون نانوية مزدوجة الجدار ونابيب كاربون نانوية متعددة الجدار == Enhancement of Al 6061 - T6 Alloy Surface Properties using Laser Cladding with DWCNTs and MWCNTs
Author name:
حسنين مجيد حسين
General topic:
Laser Science
Specific topic:
Laser Applications in Mechanical Engineering
Degree:
Master
University:
University of Baghdad - Laser Institute For Postgraduate Studies
Language:
English
University location:
Baghdad
First pages:
29T197 - p.pdf
Abstract:
Industrial applications of nanomaterial in particular carbon nanotubes (CNTs) have increased from various viewpoints, such as, high performance, energy saving, cost saving, and environmental concerns. Laser cladding technique has been used successfully to modify the surface properties of materials, i.e., improving their wear and corrosion resistance. This work involves cladding aluminum alloy (Al 6061 T6) with different types of carbon nanotubes (multi - walled carbon nanotubes (MWCNTs) and double walledcarbon nanotubes (DWCNTs)) by an automated pulsed Nd : YAG laser. This was achieved by controlling selected cladding parameters whic h are laser power, pulse duration, and working frequency. The experimental investigation included microhardness, energy dispersive X - ray, corrosion resistance and microstructure topography by scanning electron microscope. At the beginning, fifteen cladded samples divided into three groups were investigated to choose the best laserparameters for the process to have almost the best homogeneous clad layer. Group one; five levels of peak power (2.7, 2.9, 3.1, 3.3, and 3.5) kW respectively where varied versus fixed pulse duration of 16 ms, working frequency of 1.5 Hz, and scanning speed of 0.5mm/s. Group two; five levels of pulse duration (12, 14, 16, 18 and 20) ms respectively where varied versus fixed peak power of 3.1 kW, working frequency of 1.5Hz, and scanning speed of 0.5mm/s. Group three; five levels of working frequency of (1.1, 1.3, 1.5, 1.7, and 1.9) Hz respectively where varied versus fixed peak power of 3.1 kW, pulse duration of 16 ms and scanning speed of 0.5 mm/s. The investigation shows that the optimum estimated laser parameters for achieving the best results at spot diameter of 3 mm were (peak power of 3.1 kW, pulse duration of 16 ms (3 ms as preheating and 13 ms as the main action time of the pulse) and working frequency of 1.5 Hz.The executed process in this work was computationally modeled using commercial multiphysics finite element analysis (FEA) software package ANSYS® Release 11 to simulating the virtual environment of laser cladding process to determine the temperature distribution in three - dimensional (3D) analysis. Results indicated that laser cladding of Al 6061 T6 using DWCNTs enhanced three of the most important of surface properties which are hardness, abrasive wear resistance and corrosion resistance more than did the MWCNTs. The distribution of the MWCNTs on the surface of Al 6061 T6 is better than that for the DWCNTs but its penetration is less. Theoretical results show that the diffusion played an important role in the cladding process.
