(1. 中南大學(xué) 數(shù)學(xué)科學(xué)與計(jì)算技術(shù)學(xué)院，長(zhǎng)沙 410083；
2. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083)
摘 要: 基于高速壓制成形的工藝原理，對(duì)金屬粉體成形過程中的高應(yīng)變率、粘性效應(yīng)和硬化速率先上升后下降的變形特性進(jìn)行分析。將非線性彈簧、線性彈簧和高應(yīng)變率Maxwell單元并聯(lián)構(gòu)成復(fù)合非線性粘彈滯體，并用來(lái)描述壓制過程中金屬粉體的高應(yīng)變率和粘性效應(yīng)特征；將非線性彈簧的形變指數(shù)視為應(yīng)變的函數(shù)，用形變指數(shù)在壓制過程中的變化來(lái)描述金屬粉體硬化速率先上升后下降的變形特征，構(gòu)建金屬粉體高速壓制成形的本構(gòu)關(guān)系。分別用線性、二次和三次函數(shù)來(lái)近似形變指數(shù)，分析相應(yīng)的應(yīng)力—應(yīng)變曲線。結(jié)果表明：所構(gòu)建的本構(gòu)方程能描述金屬粉體高速壓制成形的變形特性。
關(guān)鍵字: 高速壓制成形；高應(yīng)變率；加工硬化；應(yīng)力—應(yīng)變曲線
metal powers during high velocity compaction process
（1. School of Mathematical Science and Computing Technology, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China）
Abstract:Based on the mechanism of high velocity compaction, the deformation characteristics of metal powder during the forming process were analyzed, which include high strain rate, viscous effect and first increasing then decreasing characteristics of hardening velocity. The non-linear spring, linear spring and high strain rate Maxwell element were combined to form a composite nonlinear viscoelastic body, which was used to describe the high strain rate and viscous effect of metal powders. The deformation index of the term of nonlinear spring was viewed as a function with respect to strain, and the change of deformation index was used to describe the first increasing then decreasing characteristics of hardening velocity of powder in high velocity compaction. The constitutive relation of metal powder in high velocity compaction was established. The deformation function was approximated to deformation index by linear, quadratic and cubic polynomial and the corresponding stress—strain curves were analyzed respectively. The results indicate that the deformation characteristics of metal powder in high velocity compaction can be described by the constitutive equation.
Key words: high velocity compaction; high strain rate; work hardening; stress—train curve
