球形压痕的残余变形分析

球形压痕技术在材料力学属性，诸如硬度，弹性模量等的测量中得到了广泛的应用。应用Twyman-Green及云纹干涉法并配合相移技术，本文对IN783合金进行了一系列的球形压痕实验研究，并对残余压痕的面内（u,v）及离面（w）变形场进行了定量测量和分析。应用面内变形测量结果，进一步对试件表面的应力一应变分布进行了分析和计算，并在离面变形场的基础上，确立了压痕周围的弹塑性边界，从而进一步应用面内的分析结果，得到材料的屈服强度。应用压痕实验的接触半径和压力并配合Tabor经验公式，本文进一步得到了材料的应力应变曲线。实验结果与已知的IN783合金相吻合。对所涉及的一系列压痕实验，本文也进行了二维有限元分析并得到了比较一致的结果。

Residual Surface Deformation Analyses Using Spherical Indentation

Spherical indentation technique was widely used for material mechanical property evaluation, such as hardness, elastic modulus etc. Using this technique, a series of residual surface deformation analyses was conducted on IN783 alloy to evaluate the material mechanical properties. Both of the residual in-plane (u, v) and out-of-plane (w) displacements were measured using a combined phase-shifting Twyman-Green and moiré interferometry. Based on the measured in-plane displacements, the surface stress-strain distribution was then analyzed. The elastic-plastic boundary was determined based on the measured out-of-plane displacements and material yield strength was obtained based on the measured in-plane displacements. Furthermore, the measured contact radii and applied loads were used to establish a post-yielding stress-strain relationship using Tabor's empirical relation. The results matched well with the known IN783 mechanical properties. Detailed 2D finite element analyses were also conducted for each loading case to study the characteristics of the residual surface deformation. The numerical results confirmed the observation from the experimental tests.