金属相含量对TiCN基金属陶瓷显微硬度的影响

Influence of Metallic Binder Content on the Microhardness of TiCN-Based Cermet

摘要:

对不同金属含量(5种，Mo：Ni为2：1)的TiCN基金属陶瓷进行显微硬度测试，加载范围从0．49N～9．8N，每个试样的显微硬度数值体现出压痕尺寸效应(ISE)。从能量平衡角度对ISE作出理论解释，认为在压痕过程中只有一部分荷载功转化为材料发生不可逆体积形变所消耗的能量，荷载功的额外消耗是表观硬度随压痕尺寸增大而减小的主要原因。真实硬度随着金属相含量的增加而降低，这是由于金属相的硬度比TiCN基体低的缘故。

Abstract:

Microhardness testing was conducted on a series of TiCN-based cermets with different contents of metallic binders (5 binders, Mo?Ni=2?1) in the applied load range from 0.49 N to 9.8 N. Significant indentation size effect in the measured microhardness was observed for each test sample. Based on the energy-balance consideration, a new theoretical explanation is presented for the indentation size effect of microhardness of test sample. It is shown that only part of the work done by applied load has been transformed into the energy to cause the irreversible volume deformation of material during indentation. The extra dissipation of the work done by applied load is the main cause for decreasing tendency of microhardness with increased indentation size. The load-independent hardness was found to decrease with the increasing metallic binder content. This can be attributed to the fact that the hardnesses of metallic binders are lower than that of the TiCN matrix.