本文主要研究内容
作者叶唯娟（2019）在《激光选区熔化过程中熔池温度场及形貌演化的数值模拟》一文中研究指出：作为当前制造业的前沿技术,激光增材制造能够实现高性能金属构件的无模具、高柔性、快速近净成形,具有非常广阔的应用前景。激光增材制造主要包括激光立体成形和激光选区熔化两种技术。对激光选区熔化而言,其过程涉及复杂多物理场耦合行为,仅通过实验观测很难获得精准的熔池形貌、尺寸及温度场等演化信息,从而限制了成形质量的控制与优化。数值模拟技术具有易操作、成本低等优点,为激光选区熔化研究开辟了一条有效途径。本文采用FLOW-3D模拟软件,研究了TC4钛合金激光选区熔化单层单道以及单层多道扫描过程中熔池温度场分布和形貌的演化规律,探讨了激光选区熔化过程中成形缺陷的形成原因,并阐述了熔池流动演化规律及机理,研究结果可为激光选区熔化工艺参数选择及优化提供指导。论文的主要结论如下:1.获得了不同工艺参数下,激光选区熔化熔池温度场及形貌尺寸的演化规律。随着扫描功率的增加,熔池最高温度随之增加,熔深和熔宽也增加;而随着扫描速度的增加,熔池最高温度降低,熔深随之也降低,但熔长反而增大;同时发现,当粉末颗粒粒径较小时,能够获得优异的表面质量。以表面粗糙度为量化标准,确定了最优工艺参数为:激光功率P=500W,扫描速度v=0.8m/s,粉末粒径d=15xm-30μm。2.球化现象形成最根本原因是粉末层没有吸收到足够的热量而使基板熔化,提高激光功率和降低粉末层厚度是有效消除球化现象的有效方法;而随机排布的粉末在熔池边缘与熔池不规则粘附必然导致不平直现象,细化颗粒可有效减小但不能彻底消除扫描过程中的单道不平直现象。3.获得了多道扫描过程中扫描路径和扫描间距对熔池缺陷的影响规律。相对于S型扫描路径,Z型扫描方式能够有效消除折返处的热量积累;扫描间距应等于单道有效宽度,即基板熔化区域的宽度,这样能够有效提高熔化沉积效率和能量利用率。4.随着激光输入能量的增大,熔池内的对流加速了传热传质,熔池内的流体由内向外传输,熔池变得宽而浅,能得到致密的粉末层,熔池内的熔体有明显从高温区向低温区运动的趋势;反冲压力除了使光斑处产生凹陷,也使熔池有向后流动的趋势。
Abstract
zuo wei dang qian zhi zao ye de qian yan ji shu ,ji guang zeng cai zhi zao neng gou shi xian gao xing neng jin shu gou jian de mo mo ju 、gao rou xing 、kuai su jin jing cheng xing ,ju you fei chang an kuo de ying yong qian jing 。ji guang zeng cai zhi zao zhu yao bao gua ji guang li ti cheng xing he ji guang shua ou rong hua liang chong ji shu 。dui ji guang shua ou rong hua er yan ,ji guo cheng she ji fu za duo wu li chang ou ge hang wei ,jin tong guo shi yan guan ce hen nan huo de jing zhun de rong chi xing mao 、che cun ji wen du chang deng yan hua xin xi ,cong er xian zhi le cheng xing zhi liang de kong zhi yu you hua 。shu zhi mo ni ji shu ju you yi cao zuo 、cheng ben di deng you dian ,wei ji guang shua ou rong hua yan jiu kai bi le yi tiao you xiao tu jing 。ben wen cai yong FLOW-3Dmo ni ruan jian ,yan jiu le TC4tai ge jin ji guang shua ou rong hua chan ceng chan dao yi ji chan ceng duo dao sao miao guo cheng zhong rong chi wen du chang fen bu he xing mao de yan hua gui lv ,tan tao le ji guang shua ou rong hua guo cheng zhong cheng xing que xian de xing cheng yuan yin ,bing chan shu le rong chi liu dong yan hua gui lv ji ji li ,yan jiu jie guo ke wei ji guang shua ou rong hua gong yi can shu shua ze ji you hua di gong zhi dao 。lun wen de zhu yao jie lun ru xia :1.huo de le bu tong gong yi can shu xia ,ji guang shua ou rong hua rong chi wen du chang ji xing mao che cun de yan hua gui lv 。sui zhao sao miao gong lv de zeng jia ,rong chi zui gao wen du sui zhi zeng jia ,rong shen he rong kuan ye zeng jia ;er sui zhao sao miao su du de zeng jia ,rong chi zui gao wen du jiang di ,rong shen sui zhi ye jiang di ,dan rong chang fan er zeng da ;tong shi fa xian ,dang fen mo ke li li jing jiao xiao shi ,neng gou huo de you yi de biao mian zhi liang 。yi biao mian cu cao du wei liang hua biao zhun ,que ding le zui you gong yi can shu wei :ji guang gong lv P=500W,sao miao su du v=0.8m/s,fen mo li jing d=15xm-30μm。2.qiu hua xian xiang xing cheng zui gen ben yuan yin shi fen mo ceng mei you xi shou dao zu gou de re liang er shi ji ban rong hua ,di gao ji guang gong lv he jiang di fen mo ceng hou du shi you xiao xiao chu qiu hua xian xiang de you xiao fang fa ;er sui ji pai bu de fen mo zai rong chi bian yuan yu rong chi bu gui ze nian fu bi ran dao zhi bu ping zhi xian xiang ,xi hua ke li ke you xiao jian xiao dan bu neng che de xiao chu sao miao guo cheng zhong de chan dao bu ping zhi xian xiang 。3.huo de le duo dao sao miao guo cheng zhong sao miao lu jing he sao miao jian ju dui rong chi que xian de ying xiang gui lv 。xiang dui yu Sxing sao miao lu jing ,Zxing sao miao fang shi neng gou you xiao xiao chu she fan chu de re liang ji lei ;sao miao jian ju ying deng yu chan dao you xiao kuan du ,ji ji ban rong hua ou yu de kuan du ,zhe yang neng gou you xiao di gao rong hua chen ji xiao lv he neng liang li yong lv 。4.sui zhao ji guang shu ru neng liang de zeng da ,rong chi nei de dui liu jia su le chuan re chuan zhi ,rong chi nei de liu ti you nei xiang wai chuan shu ,rong chi bian de kuan er jian ,neng de dao zhi mi de fen mo ceng ,rong chi nei de rong ti you ming xian cong gao wen ou xiang di wen ou yun dong de qu shi ;fan chong ya li chu le shi guang ban chu chan sheng ao xian ,ye shi rong chi you xiang hou liu dong de qu shi 。
论文参考文献
论文详细介绍
论文作者分别是来自西安理工大学的叶唯娟，发表于刊物西安理工大学2019-07-19论文，是一篇关于激光选区熔化论文,介观模拟论文,温度场论文,熔池形貌论文,熔池流动论文,西安理工大学2019-07-19论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自西安理工大学2019-07-19论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：激光选区熔化论文; 介观模拟论文; 温度场论文; 熔池形貌论文; 熔池流动论文; 西安理工大学2019-07-19论文;