BN含量对ZrBN合金组织与性能的影响

利用OM、SEM、XRD、维氏硬度以及力学性能试验机等,研究了非自耗电弧熔炼炉制备的ZrBN合金(BN=0.5wt%,0.7wt%,1.0wt%,1.5wt%,2.0wt%)的显微组织、断口形貌、相结构以及力学性能。结果表明:加入BN后,合金中出现了金属间化合物ZrB₂相的衍射峰,且强度随着BN含量的增加而升高。随着BN的加入,合金晶粒尺寸明显细化,且分布均匀,在BN含量到达1.5wt%之后,棒状ZrB₂相尺寸急剧增大。当合金中BN含量为0.5wt%时,合金表现出良好的综合力学性能,其最大压缩强度、屈服强度以及压缩塑性分别为1311 MPa、928 MPa以及16.71%,压缩断口呈韧性断裂模式。随着BN含量的增加,合金的塑韧性显著降低,压缩断口逐渐转呈现为脆性断裂。

Effect of BN content on microstructure and properties of ZrBN alloys

As-cast ZrBN alloys( BN = 0. 5 wt%,0. 7 wt%,1. 0 wt%,1. 5 wt%,2. 0 wt%) were prepared via non-consumable arc melting furnace under Ar atmosphere. The effect of the BN content on the phase structure,microstructure and mechanical properties of the Zr BN alloys were examined by means of optical microscopy( OM),scanning electron microscope( SEM),X-ray diffraction( XRD),microhardness tester and mechanical properties testing system. The results show that the diffraction peaks of the intermetallic ZrB2 phase are presented after BN addition,and their intensities increase with the BN content increasing. With the addition of BN,the grain size of the alloys is obviously refined and evenly distributed,while the size of the rod-like ZrB2 phase increases rapidly when the BN content reaches 1. 5 wt%. When the BN content is 0. 5 wt%,the alloy possesses excellent comprehensive mechanical properties,with the compressive strength,yield strength and compressive plasticity being 1311 MPa,928 MPa and 16. 71%,respectively,and the compressive fracture morphology presents the ductile fracture mode. Whereas,when the BN content is increased further,the ductility of the alloys dramatically declines,and the compressive fracture changes gradually to the brittle one.