Deformation Behavior and Damage Evaluation in a New Titanium Diboride (TiB2) Steel‐Based Composite
Deformation Behavior and Damage Evaluation in a New Titanium Diboride (TiB2) Steel‐Based Composite
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DOI：
10.1002/srin.201100255
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发表时间：
2012-06
影响因子：
2.2
通讯作者：
Z. Hadjem-Hamouche;J. Chevalier;Yi-xiang Cui;F. Bonnet
中科院分区：
文献类型：
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作者：
Z. Hadjem-Hamouche;J. Chevalier;Yi-xiang Cui;F. Bonnet
采用扫描电镜原位三点弯曲试验研究了一种新型复合钢的变形行为和损伤评价。二硼化钛（TiB2）增强钢复合材料是由TiB2颗粒在共晶凝固过程中原位析出而产生的。安赛乐米塔尔开发的这种生产工艺使钢复合材料的比刚度显著提高（约20%），并且具有良好的强度和延展性。所得到的显微组织包括由铁素体和TiB2粒子的共晶混合物包围的TiB2初生晶体。损伤的主要形式是颗粒断裂和基体的不均匀塑性变形。与其他生产工艺相比，颗粒断裂比界面脱粘更为常见，说明界面强度不是该复合材料损伤积累和断裂的限制因素。裂纹扩展发生在裂纹尖端前的颗粒断裂，产生大的微孔，然后通过剩余基体韧带的延性破坏与裂纹扩展连接。结果还表明，裂纹倾向于避免直接的粒子相互作用。
Deformation behavior and damage evaluation of a new composite steel has been investigated by means of in situ three‐point bend tests in the scanning electron microscope. The titanium diboride (TiB2)‐reinforced steel composite is produced by in situ precipitation of the TiB2 particles during eutectic solidification. This production process developed by ArcelorMittal leads to a steel composite with a significant increase in specific stiffness (>20%), and good strength/ductility compromise. The microstructures obtained consist of primary TiB2 crystals surrounded by a eutectic mixture of ferrite and TiB2 particles. The primary mode of damage is particle fracture and inhomogeneous plastic deformation in the matrix. In contrast with other production process, particle fracture was more common than interfacial debonding indicating that interfacial strength is not the limiting factor in damage accumulation and fracture in this composite. Crack growth occurred by particle fracture ahead of the crack tip, producing large microvoids, which then link up to the growing crack by ductile failure of the remaining matrix ligaments. The results suggest also that the cracks tended to avoid direct particle interactions.