热成形金属复合材料的微观结构及力学行为研究

Microstructure and Mechanical Behavior of New Type Multi-layer Metallic Composite Material in Hot Forming

对汽车车门防撞梁热成形(成形与淬火同时进行)过程进行了研究,发现由于成形过程中钢材表面发生氧化脱碳,得到的防撞梁零部件表面软而内部硬,材料性质在厚度方向上呈连续梯度分布,即表面硬度、强度低而内部的硬度、强度高,这样形成了新型连续梯度分布的多层金属复合材料。对汽车车门防撞梁这种新型金属复合材料的微观结构、硬度、强度及塑性变化规律进行研究,并进行三点弯曲对比实验。在此基础上研究这种新型金属复合材料的碰撞及吸能性能,根据金相分析及三点弯曲实验建立了防撞梁的有限元分析模型。通过对比金属复合材料与内部各相材料冲击时所受到的冲击力、吸能等性能,发现这种新型金属复合材料综合了各单相材料的优秀性能,适合用于承受冲击吸能构件的选材。

The hot forming（quenching and forming at the same time） oxidizes and decarburizes the steel surface.The automotive components and parts formed in this technique show soft surface and hard inside.The material properties present gradient distributions in the thickness direction.The exterior hardness and strength are low,while the interior hardness and strength are high.Then the new type multi-layer metallic composite material is formed.To investigate the crashworthiness of the new metallic composite materials,the hot forming stamping pieces are experimentally and numerically studied.Taking the door reinforced beam for the samples,the three-point bending was carried out by experiment and finite element analysis（FEA）.By comparing the crash force and energy absorption between the metallic composite materials and its every single phase material,it is found that the metallic composite materials have the comprehensive performance of every single phase material.So the new metallic composite material is a good alternative material in application of absorbing energy.