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在本文中,采用160,200,230,250℃四种温度和0.5×10~(-2),0.75×10~(-2),1×10~(-1),1.5×10~(-1)min~(-1)四种应变速率对于 Zn-22%Al 共析合金的 m-C-δ或 m-k-δ关系(简称 m-δ关系)曲线进行了研完。在曲线上表现为,m 值在一定的应变量(“极限”应变量)以内,随应变(δ)的增加而快速增高。超过“极限”应变量后,变为缓慢增高或缓慢下降,直到断裂。因此,可以肯定在一定的条件下,存在和该合金的起始应变δ_0(=0.00%)拉伸期间各个阶段的瞬时应变,δ_Ⅰ(δ_(Ⅰ1),δ_(Ⅰ2),δ_(Ⅰ3),……),拉断时的总延伸率δ_(?)相对应的 m_0(≠0),m_Ⅰ(m_(Ⅰ1),δ_(Ⅰ2),δ_(Ⅰ3),……),m_F 值和 k_0(≠0),k_Ⅰ(k_(Ⅰ1),k_(Ⅰ2),k_(Ⅰ3),……),k_F 值。C_0=k_Ⅰ/k_0=1,C_Ⅰ=k_Ⅰ/k_0,C_F=k_F/k_0(见方程式,σ=kε~m,其中σ为流变应力,(?)为应变速率,m 为流变应力的应变速率敏感性指数,k 为系数[1])。m,δ和 C 之间的关系可以由下面的 m-δ关系式(或称 L.Q.方程式)[2,3]表达:δ_F(%)=[C_F(?)~(m~F-m~(?))-1]×100(试棒拉断)或δ_Ⅰ(%)=[C_Ⅰ(?)~(m_Ⅰ-m_0)-1]×100(试棒不拉断)其中 m_0 和 C(C_Ⅰ和 C_F)均为任意常数~**由实测 m-δ关系曲线外推,获得了各试验条件下的 m_0和 m_F 值。由有关数据,根据 L、Q、m-δ方程式计算出来了和不同应变量(δ)相对应的 C(C_Ⅰ和 C_F)值。C-δ关系成近似的直线关系。直线的斜率在“极限应变”处发生突然减小。
In this paper, four temperatures of 160, 200, 230, and 250 ℃ were used in this study. 1) The four strain rates were studied for the mC-δ or mk-δ (abbreviated m-δ relationship) curve for Zn-22% Al eutectoid. On the curve, m is within a certain amount of strain (“limit” strain) and increases rapidly with increasing strain (δ). After the “limit” strain is exceeded, it slowly increases or falls slowly until it breaks. Therefore, it can be confirmed that under certain conditions, the instantaneous strain, δ_Ⅰ (δ_ (Ⅰ), δ_ (I_2), δ_ (I_3), δ_ ...), m_0 (≠ 0), m_I (m_ (I1), δ_ (I2), δ_ (I3), ...) corresponding to the total elongation δ_ ≠ 0), k_I (k_ (I1), k_ (I2), k_ (I3), ...), k_F values. C_0 = k_I / k_0, C_F = k_F / k_0 (see the equation, σ = kε ~ m, where σ is the flow stress, σ is the strain rate and m is the strain of the flow stress Rate Sensitivity Index, k is the coefficient [1]). The relationship between m, δ, and C can be expressed by the following m-δ (or LQ) equations [2,3]: δ_F (%) = [C_F (?) ~ (m ~ Fm ~ ) -1] × 100 (test bars pulled off) or δ_I (%) = [C_I (?) ~ (M_I_m_0) -1] × 100 (test bars not broken off) where m_0 and C (C_I and C_F) Are arbitrary constants ~ ** Measured by extrapolation of the measured m-δ curve obtained m_0 and m_F values of each experimental conditions. From the relevant data, C (C_I and C_F) values corresponding to different strain quantities (δ) are calculated according to L, Q, m-δ equations. C-δ relationship into a similar linear relationship. The slope of the line suddenly abruptly decreases at “ultimate strain”.