球头压痕确定薄膜模量的等效膜厚法

针对名义成分为Ti-46Al-3.8(V,Cr,Ni) (at％)的挤压TiA1合金,研究了热处理工艺对高温时β相含量、形貌的影响,利用高温时β相对α相晶粒的钉扎作用获得了层片团尺寸均匀、细小的全层片组织,测试了具有该组织合金的拉伸性能.结果表明,在1320～1370℃范围内,随保温温度的升高,β相含量逐渐增加,使得合金的晶粒尺寸逐渐减小.实验合金经1340℃/5 min/AC热处理后可以获得层片团(尺寸平均为65 μm),B2相弥散分布的全层片组织.该组织的室温及高温拉伸性能均较好.少量B2相对合金的室温塑性无不利影响,对合金的高温强度可能有一定贡献.

Determination of the Elastic Modulus of Thin Film by Spherical Indentation Based on Equivalent Film Thickness Model

Based on the Hertz equation, an equivalent film thickness method using spherical indentation was proposed to determine the modulus of thin films by means of modifying the mechanical model of flat cylindrical indentation. The FEM results verified by RW model show that the?error of the proposed model is less than?RW model when?the elastic modulus of film?is greater than that of the substrate; on the contrary, the results of the present method still agree well with the theoretic value while the indentation is much deeper. Therefore this model could be used to the instance that the indentation is more severe. In addition, the influences of yield strength of thin films and radius of the ball on the results were studied. It is found that the greater the yield strength of the thin films is, the smaller the error derived by proposed model is. At the same time, with the increase of the indenter radius, the error is greater under the same indentation depth. Furthermore, the influence of the radius on the modulus is smaller when the indentation is shallow. The proposed model is verified by indentation experiment on TiN/sapphire with Spherical indenter and Berkovich indenter