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利用相同的激光熔覆工艺条件,在H13钢基材上制备了不同TiC颗粒含量的H13-TiC复合涂层。采用准静态拉伸实验,获得了复合涂层的弹塑性应力应变曲线。实验结果显示,复合涂层达到屈服强度后,硬化效应明显;颗粒含量提高,其弹性模量和屈服强度相对增加,但抗拉强度变化不明显。利用扫描电镜(SEM)观测试样拉伸后的断口形貌,在TiC颗粒含量较低的情况下,断口分布有大量韧窝,呈韧性断裂,随着TiC颗粒的增多,断裂方式从韧性向脆性转变。基于Mori-Tanaka平均场理论,耦合ABAQUS子程序UMAT,对颗粒增强复合涂层进行了弹塑性的数值模拟,在一定误差范围内,理论预测与实验结果基本吻合。
Using the same laser cladding process conditions, H13-TiC composite coatings with different content of TiC particles were prepared on H13 steel substrate. The quasi-static tensile test was used to obtain the elastic-plastic stress-strain curve of the composite coating. The experimental results show that after the composite coating reaches the yield strength, the hardening effect is obvious. When the content of the particles increases, the elastic modulus and yield strength increase relatively, but the tensile strength does not change obviously. Scanning electron microscopy (SEM) was used to observe the fracture morphology after tensile test. In the case of low content of TiC particles, a large number of dimples were distributed in the fracture with ductile fracture. With the increase of TiC particles, the fracture mode changed from ductile Brittle transition. Based on the Mori-Tanaka mean field theory and the coupled ABAQUS subroutine UMAT, the elasto-plastic numerical simulation of particle-reinforced composite coatings was carried out. The theoretical predictions are in good agreement with the experimental results within a certain error range.