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レーザー照射による金属および半導体の溶融蒸発過程の研究

激光辐照金属和半导体熔化与蒸发过程研究

基本信息

批准号：
07219203
负责人：
大村悦二
金额：
$ 1.34万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1995
资助国家：
日本
起止时间：
1995 至无数据
项目状态：
已结题

项目摘要

穴あけ,切断などのレーザ加工では,プラズマや超微粒子が生成するなど,複雑な溶融・蒸発現象を伴う.これらの現象を明らかにするには,原子オーダーで直接観察できないため,実験以外の微視的解析も必要である.一つの試みとして,昨年度は,結晶のレーザ光吸収モデルを提案し,fcc金属を対象として分子動力学シミュレーションを行った.そして,溶融・蒸発時の原子挙動と応力状態,衝撃波の伝播,蒸発粒子の形態と生成過程などを明らかにした.本年度は,Nd: YAGレーザ4次高調波を照射した際の,Si単結晶の溶融・蒸発過程を分子動力学シミュレーションした.また,自由電子による熱伝導を考慮しながら分子動力学計算を進める改良型分子動力学法を提案し,その妥当性を検討した.得られた結論を要約すると,以下のようになる: I. Siの溶融・蒸発について(1)熱衝撃波速度はレーザのパワー密度によらず一定で,fcc金属の場合と同様,材料の弾性波速度に等しい.(2)穴あけ加工では,フルエンスが比較的小さいときは,穴の深さや除去量はフルエンスにほぼ比例するが,フルエンスが大きくなると比例しなくなる.フルエンスが同じ場合は,エネルギー密度が高い方が除去量は多い.(3)加工穴周囲にはうずたかい盛上りが生じる.これは蒸発原子が堆積したものである.(4)加工痕表面は凹凸が激しく,加工表面近傍に空孔などの格子欠陥が顕著になる. II.改良型分子動力学法について(1)改良型分子動力学法で算出した金属の熱伝導率は,文献値とよく一致する.(2)したがって,本方法は従来型分子動力学法より金属の熱伝導現象をよくシミュレートできる.(3)金属のレーザ加工における除去深さや溶融凝固層深さなどは,改良型分子動力学シミュレーションによって推定する方がよい.(4)熱衝撃現象や蒸発形態については,従来型分子動力学シミュレーションでもほぼ妥当な結果が得られる.

In addition, the ultra-fine particles are generated during the cutting process, and the melting and evaporation phenomenon are accompanied by the re-melting. This phenomenon is clearly visible, atomic and direct observation, and analysis of Weishi app is necessary. A new approach to molecular dynamics was proposed in the field of crystal light absorption. In addition, the atomic motion and force state during melting and evaporation, the propagation of shock waves, and the morphology and generation process of evaporated particles are clearly described. This year,Nd: YAG crystals were irradiated for the fourth time with high-frequency radiation, and the molecular dynamics of the melting and evaporation process of Si crystals was studied. Free electron thermal conduction is considered, molecular dynamics calculations are advanced, improved molecular dynamics methods are proposed, and their appropriateness is discussed. If we conclude this conclusion, we will make the following remarks: I. Si melting and evaporation (1) Thermal shock wave velocity is equal to the density of Si, and the same is true for fcc metals. (2)The proportion of hole processing is smaller than that of hole processing, and the proportion of hole processing is larger than that of hole processing. In the same case, the density of the product is high, the removal amount is high, and the removal amount is high. (3)Processing hole week This is the first time I've ever seen an atom pile up. (4)The machined surface is uneven, and the machined surface is near the hole. II. Improved molecular dynamics method (1) Improved molecular dynamics method to calculate the thermal conductivity of metals. (2)This method is based on the molecular dynamics method to investigate the thermal conductivity of metals. (3)In the process of metal processing, the deep melting and solidification layer is removed, and the modified molecular dynamics model is used to estimate the solution. (4)The thermal shock phenomenon and the evaporation morphology are different from each other, and the molecular dynamics model is different from each other.