大连理工&江苏大学增材顶刊：新办法！实现600MPa铝合金增材制造
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;"><span style="color: black;">因为</span>Al-Zn-Mg-Cu合金<span style="color: black;">很强</span>的凝固区间（约150 K），热膨胀系数高，开裂<span style="color: black;">敏锐</span>性大，熔体流动性差，导热系数高等特性，激光粉末床熔化技术（LPBF）快速熔凝过程中易<span style="color: black;">显现</span>热裂纹；电弧增材制造（WAAM）中电弧的热输入<span style="color: black;">很强</span>，熔池的凝固速率较小，看上去能够<span style="color: black;">处理</span>Al-Zn-Mg-Cu合金LPBF过程易生裂纹的制造<span style="color: black;">困难</span>，遗憾的是，WAAM过程的高热输入<span style="color: black;">一样</span>会促进粗大晶粒、气孔以及元素偏析的形成，这将<span style="color: black;">引起</span>性能的各向异性和拉伸强度的降低。</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">基于此，</span><strong style="color: blue;"><span style="color: black;">大连理工大学机械工程学院马广义、吴东江教授与江苏大学鲁金忠、罗开玉教授合作，提出激光-电弧复合增材制造新<span style="color: black;">办法</span>，<span style="color: black;">处理</span>Al-Zn-Mg-Cu合金的增材制造<span style="color: black;">困难</span>，</span></strong><span style="color: black;"><span style="color: black;">关联</span>论文以题为“Superior strength of laser-arc hybrid additive manufactured Al-Zn-Mg-Cu alloy enabled by a tunable microstructure”，<span style="color: black;">发布</span>在增材制造顶级期刊《Additive Manufacturing》上。</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">论文链接：</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">https://doi.org/10.1016/j.addma.2023.103526</span></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/927a95b7797445e0a28f3f1929db0352~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=1JcJULWTEMaVoFvvwEEJlsyUoPg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">该技术采用定域可控的脉冲激光<span style="color: black;">做为</span>热源之一，与热输入<span style="color: black;">很强</span>的电弧复合<span style="color: black;">一起</span>熔化焊丝，<span style="color: black;">经过</span>激光与电弧的协同<span style="color: black;">功效</span>，</span></strong><span style="color: black;">制备出Al-Zn-Mg-Cu合金样件，<span style="color: black;">科研</span>了激光-电弧复合增材过程微观组织的形成机制，以及随后的固溶+时效热处理对组织和力学<span style="color: black;">行径</span>的影响。在平行于沉积方向的截面上观察到双峰异质组织，即电弧区柱状晶粒和激光区等轴晶粒交替分布。η-MgZn2相在电弧区晶界处形成<span style="color: black;">繁杂</span>的连续网状，而在激光区为晶内离散、均匀分布的颗粒形态。<span style="color: black;">经过</span>TEM观察到60-100 nm的棒状η相，与Al基体为非共格界面，对力学性能的<span style="color: black;">提高</span>较少。经过热处理后，η相<span style="color: black;">出现</span>溶解，激光区和电弧区的元素和析出相分布趋于一致化，晶粒<span style="color: black;">无</span><span style="color: black;">出现</span>再结晶。高密度的η′相与Al基体为半共格界面，是Al-Zn-Mg-Cu合金中最<span style="color: black;">重点</span>的强化相，与基体晶格<span style="color: black;">摆列</span>相同的GP-Ⅱ区<span style="color: black;">周边</span>晶格会畸变，形成共格应变场，<span style="color: black;">亦</span>能够起到强化<span style="color: black;">功效</span>。</span><strong style="color: blue;"><span style="color: black;">热处理态的Al-Zn-Mg-Cu合金的抗拉强度达到602.3 ± 7.6 MPa，断后伸长率为8.90 ± 0.10 %，</span></strong><span style="color: black;">该合金的综合力学性能优于大<span style="color: black;">都数</span>LBPF制备和WAAM制备的Al-Zn-Mg-Cu、Al-Cu以及Al-Mg(Si)合金，</span><strong style="color: blue;"><span style="color: black;">能够与常规锻造的7075铝合金相媲美。</span></strong></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/06527eb087d44043ba4aeea974c730dc~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=eKQO%2FDX2EkGl4WNr8aL9PNlY%2Fw4%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">图1 （a）晶粒形态演变示意图；（b）柱状晶和等轴晶的IPF图。</span></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/c80182fc5b724474b7456ba4bb961743~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=Xc%2FJ2xi2g9sp0muiruqRDO%2B7a30%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">图2沉积态Al-Zn-Mg-Cu合金的SEM和EDS：（a）显微组织，（b）AZ的放大视图，（c）LZ的放大视图，（d）第二相及其选区的元素分布。</span></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/9da774fd17074adc8e99d15d8a4070c6~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=Huo%2FdTXSPWDzREOgdnQEG2i60cg%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">图3 （a）热处理态Al-Zn-Mg-Cu合金的典型HRTEM。（b）（a）图中红框区域的对应SAED和析出相的元素分布。（c）GP-II区的HRTEM和SAED。（d）（c）图中标记区域的反FFT。（e）<span style="color: black;">经过</span>GPA<span style="color: black;">办法</span>计算的应变场。</span></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/dd1e74ed5816407a81c66acce6e10d33~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=YKq71%2FUxq24YXVpI7YuTux4998U%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">图4 沉积态和热处理态Al-Zn-Mg-Cu合金的力学性能：（a）拉伸应力-应变曲线，（b）横向和纵向拉伸性能，（c）本工作中与LPBF和WAAM制造的其他Al-Zn-Mg-Cu、Al-Cu和Al-Si（Mg）合金的力学性能比较</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">与此<span style="color: black;">同期</span>，结合熔池凝固过程CFD模拟，探讨了激光-电弧复合过程中独特的微观组织的形成及演变机理。本<span style="color: black;">科研</span>采用的脉冲激光的峰值功率为2000 W，产生小孔效应，脉冲激光加入瞬间，熔池内部温度<span style="color: black;">上升</span>，在脉冲激光结束时刻达到最大值。当仅电弧<span style="color: black;">功效</span>于熔池时，熔池内部的平均温度梯度约为104 K/m，激光<span style="color: black;">功效</span>瞬间增大至105K/m，G/R值降低，晶粒向粗大柱状晶生长的趋势减弱，<span style="color: black;">更易</span>转变为等轴晶。脉冲激光周期性的能量输入，加快了熔池对流，<span style="color: black;">加强</span>熔池凝固速率，促进了溶质元素的充分扩散。</span></span></p>
<div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/d340551f9ccd4b2db158f8c5927a40bd~noop.image?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1728800807&x-signature=hsvijy9pz%2BJ5cjYUI5oBUbT8B%2FY%3D" style="width: 50%; margin-bottom: 20px;"></div>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">图5 激光-电弧复合增材热历程：（a）t=0 ms时2D切片和3D温度场，（b）t=0 ms时2D切片和3D温度场，（c）Section B的<span style="color: black;">区别</span>区域的热历程，（c）沿Z方向的固/液界面温度梯度与凝固速率变化。</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;"><span style="color: black;">另一</span>，定量计算了Al-Zn-Mg-Cu合金的强化机制，<span style="color: black;">重点</span><span style="color: black;">包含</span>晶界强化、固溶强化、沉淀强化。晶界强化对屈服强度的贡献约为4.5%，Zn、Mg和Cu三种元素的沉淀强化为16.5%，而η′相和GP-Ⅱ区<span style="color: black;">导致</span>的沉淀强化对屈服强度的贡献高达75.1%。<span style="color: black;">另外</span>，激光-电弧复合增材制造的Al-Zn-Mg-Cu合金样件的纵向力学性能均<span style="color: black;">小于</span>横向样件，呈现各向异性。与沉积态样件相比，经过热处理后UTS各向异性百分比降低了约65%。</span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">*感谢论文作者团队对本文的大力支持。</span></strong></span></p>
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