Fiber及Nd：YAG雷射技術對Cu-Ni-Si-Cr+Al2O3粉末冶金合金銲接修補特性之研究

Study of Fiber and Nd：YAG LASER techniques for the repair welding of the powder metallurgy Cu-Ni-Si-Cr+Al2O3

何姿瑩(Tzu-Ying Ho)

指導教授 ： 王惠森

義守大學/工學院/材料科學與工程學系/碩士(2023年)

摘要

為探討熱處理前後與Fiber LASER及Nd：YAG銲接參數對Cu-Ni-Si-Cr+Al2O3合金銲接修補特性之影響，本研究將透過Nd：YAG及Fiber LASER銲接技術，搭配銲前、銲後固溶及時效熱處理及不同銲接參數設計，對粉末冶金製成的Cu-Ni-Si-Cr+Al2O3(Cu-7.04Ni-1.70Si-0.42Cr+1.1Al2O3)合金進行銲接修補。並針對銲接修補後試片，進行銲後熱處理提升銲補件的機械強度。後續將針對銲前及銲後熱處理之試片進行微組織觀察、成分分析、機械性質及熱物性質之分析及比較。
實驗結果顯示，Cu-Ni-Si-Cr+Al2O3合金經Nd：YAG及Fiber LASER銲補件進行固溶時效熱處理後，兩者之強化機制非常的相似，藉由TEM微組織觀察結果得知，兩種銲接程序所產生WFZ析出強化相皆為奈米級δ-Ni2Si及α-Al2O3與γ-Al2O3，而HAZ的Grain A及Grain B析出強化相為δ-Ni2Si。時效熱處理後Nd：YAG在WFZ、HAZ及未受熱影響之各區域其硬度值最低308 Hv，最高可至328 Hv，透過最低硬度值可預估銲補件拉伸強度可達807 MPa以上，熱傳導係數可達135 W/mK；而Fiber LASER在WFZ、HAZ及未受熱影響區之各區域其硬度值305 Hv，最高可至329 Hv，透過最低硬度值可預估銲補件拉伸強度接近800 MPa，熱傳導係數可達到133 W/mK以上。在經過時效熱處理後無論是Nd：YAG或Fiber LASER其不同區域硬度值，與傳統鑄件時效6小時相比，時效8小時反而在銲補件的WFZ，HAZ及母材皆具有較佳硬度值，根據最低硬度值與拉伸強度及熱傳導係數關係圖，其拉伸強度與熱傳導係數皆符合模具材料要求。

關鍵字

粉末冶金 ； Cu-Ni-Si-Cr合金 ； 雷射銲接 ； 銲接修補 ； 銲後熱處理 ； 機械性質 ； 熱物性質

並列摘要

To study the effects of LASER welding parameters and heat treatment processes on the repair welding characteristics of Cu-Ni-Si-Cr+Al2O3 mold alloy, this study used Nd：YAG and Fiber LASER processes with various pre-or post- (solution and aging heat treatment) welding heat treatment processes to repair welding of Cu-7.04Ni-1.70Si-0.42Cr+1.1Al2O3 alloy, the microstructure, mechanical properties, composition analysis and thermal properties of the tested samples were then analyzed and compared.
The experimental results show, after post-welding heat treatment of Nd：YAG and Fiber LASER repair welded samples, the strengthen mechanism of both welds are similar. In the both welds, by means of TEM inspections, nanoscale δ-Ni2Si, α-Al2O3 and γ-Al2O3 precipitates were observed in the weld fusion zone (WFZ) and nanoscale δ-Ni2Si was observed in the Grain A and Grain B of the heat affected zone (HAZ), respectively.
Regarding to the mechanical and thermal properties, referred to the hardness values, the tensile strength value of the Nd：YAG welds is statistically estimated to 807 MPa, and the thermal conductivity is about 135 W/mK; For the Fiber LASER welds, the tensile strength value is statistically estimated about 800 MPa, and the thermal conductivity is about 133W/mK. Furthermore, compared to the traditional Cu-Ni-Si-Cr casting alloy (ageing heat treatment of 6h was suggested), for the Cu-Ni-Si-Cr+Al2O3 alloy, aging heat treatment of 8h has better performance than that of 6 hours.

並列關鍵字

Powder Metallurgy ； Cu-Ni-Si-Cr+Al2O3 ； LASER welding ； Heat treatment ； Mechanical properties ； Thermal properties

參考文獻

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