Mo-La 2O3 composites; Microstructure; Properties; Strengthening and toughening mechanism
摘要:
采用 X 射线衍射仪(XRD),扫描电子显微镜(SEM),维氏硬度计,
电子万能材料试验机,动态热模拟机研究了稀土钼复合材料的结构、形貌、硬
度、断裂韧性、高温屈服强度、强韧化机理等。结果表明:在钼中添加适量的
La 2 O 3 ,可起到室温强韧化和高温强化作用。随着La 2 O 3 含量的增加,样品的硬度、
断裂韧性呈先增后减的规律,其最大值分别为 10.85 GPa,7.25 MPa·m 1/2 。该
材料的强化机制为细晶优化和晶界强化;韧化机制为细晶韧化,裂纹偏转、微
桥接和弯曲韧化。
The structure, morphology, hardness, fracture toughness, high-temperature
yield strength, strengthening and toughening mechanism of Mo-La 2 O 3 composites
were investigated by means of X-ray diffraction( XRD), scanning electron microscope(
SEM), Vichers hardness tester, electrical omnipotence material tester and dynamic
heat simulate in this paper. The results showed that the ambient temperature hardness
and fracture toughness, high - temperature yield strength of the samples would
increase by adding suitable La 2 O 3 into Mo material. The hardness and toughness of
the specimens would increase, then decrease with increasing the content of La 2 O 3 ,
and their maximum value were 10.85 GPa and 7.25 MPa·m 1/2 , respectively. The
strengthening mechanisms of composites are fine grains and optimal crystal boundary
strengthening, and the toughening mechanisms are fine grain toughening and crack
deflection, the micro bridge join and the crack bend toughening.