一种新型双轴试验设备的成形极限的下烫印条件的决定
Summary
该协议提出上的电阻，以确定热冲压条件下的金属板的成形极限图（FLD）加热单轴拉伸试验机中使用的新颖的双轴测试系统。
Abstract
热冲压和冷模淬火工艺越来越多地用于形成金属片的复杂形状的结构部件。常规的实验方法，如外的平面和平面内的测试中，并不适用于加热和快速冷却处理之前形成用于热冲压条件下进行测试时引入成形极限的确定。一种新颖的平面内双轴测试系统的设计和用于形成在电阻加热单轴试验机加热和冷却过程后的不同应变路径，温度和应变率的金属板的限制的确定。双轴测试系统的核心部分是一个双轴设备，其传送由单轴试验机提供到双轴力的单轴力。十字形样品的一种类型被设计和验证的使用提出的双轴测试系统铝合金6082的成形性试验。数字IM使用年龄相关性（DIC）系统用高速照相机对变形期间采取的试样的应变测量。提出该双轴测试系统的目的是使合金的成形极限，在热冲压条件下各种温度和应变速率来确定。
Introduction
汽车行业正面临着降低燃油消耗和车辆排放减少环境污染的一个巨大的全球性挑战。轻量化对提高汽车的性能是有益的，并且可以直接降低能耗1。由于金属板在室温下，热冲压和冷模淬火工艺低的可成形性（称为热冲压）2用于改进合金的成形性并因此获得在汽车应用中复杂形状的部件。
成形极限图（FLD）是评价的合金3的成形性的有用工具。外的平面的测试，如测试Nakazima 4， 图5和面内测试，如测试Marciniak 6，7，8，一个再常规的实验方法，以获得各种条件9，10，11下的金属板的成形极限。甲伺服液压双轴测试机也已经用于研究合金在室温下12，13中的可成形性。
然而，没有上述方法适用于热冲压条件下的可成形性的测试中，因为与加热和冷却速率的控制一起，需要成形之前的冷却过程。变形温度和应变速率很难获得准确。因此，一种新的成形性的测试系统是在本研究中提出的通过实验来确定片材金属的热冲压条件下成形极限。
Protocol
Representative Results
Discussion
用于确定成形限制常规的成形性的测试方法是通常只在室温下适用。所呈现的技术可用于通过引入新颖的双轴测试设备到电阻加热单轴试验机来评价金属用于热片冲压应用的可成形性。这可以不使用用于热冲压应用的常规方法来进行。加热和冷却系统和DIC系统的设置是为了控制在样品温度分布的均匀性，并因此记录拉伸试样的变形历史的关键。
在该技术中，加热和冷却速率?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This research was supported by the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 604240, project title “An industrial system enabling the use of a patented, lab-proven materials processing technology for Low Cost forming of Lightweight structures for transportation industries (LoCoLite).”
Materials
| Aluminium Alloy | Smiths Metal | 6082 | Specimens machining |
| Laser cutter | LVD Ltd | HELIUS 25/13 | Laser cutting specimens |
| CNC machine | HAAS Automation | TM-2CE | Machine specimens by milling |
| Vernier caliper | Mitutoyo | 575-481 | Thickness measurement |
| Resistance heating uniaxial testing machine | Dynamic System Inc | Gleeble 3800 | Thermo-mechanical materials simulator |
| High flow quench system | Dynamic System Inc | 38510 | For air cooling |
| Thermocouples | Dynamic System Inc | K type | |
| Nozzles | Indexa | Nozzle flared 1/4 inch bore | |
| Welding cables | LAPP Group | H01N2-D | |
| High-speed camera | Photron | UX50 | For DIC testing |
| Camera lens | Nikon | Micro 200mm | |
| Lamp | Liliput | 150ce | 300W |
| Laptop | HP | Campaq 2530p | For images recording |
| Biaxial testing apparatus | Manufactured independently | All parts were designed and machinced by authors for biaxial testing | |
| Steel | West Yorkshire Steel | H13 | Mateials of the biaxial testing apparatus |
| Image correlation processing software | GOM | ARAMIS | Non-contact measuring system and data post-pocessing |
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