ELASTIC-CONSTANTS, HARDNESS AND THEIR IMPLICATIONS TO FLOW PROPERTIES OF METALLIC GLASSES
ELASTIC-CONSTANTS, HARDNESS AND THEIR IMPLICATIONS TO FLOW PROPERTIES OF METALLIC GLASSES
复制标题
DOI：
10.1016/0022-3093(75)90018-6
复制
发表时间：
1975-01-01
影响因子：
3.5
通讯作者：
COLEMAN, E
中科院分区：
文献类型：
--
作者：
CHEN, HS;KRAUSE, JT;COLEMAN, E
测量了（Pd 1-xNix）0.80P0.20、（Pd 1-xFex）0.80P0.20和（Pt 1-xNix）0.75P0.25金属玻璃的纵向和横向声速及维氏硬度。在室温下的弹性常数表现出与组成X的线性正偏差，而硬度显示出负偏差。弹性常数的增加归因于混合时合金的致密堆积。约化硬度Hr/μ与χ的关系与α Tg与χ的关系具有显著的相似性。这似乎表明，在玻璃化转变温度以上和以下的金属玻璃中涉及的流动机制是相似的起源。正是与合金化有关的无序的过量熵降低了金属玻璃的硬度和粘度。金属玻璃一般具有较高的泊松比ν ≥ 0.40，剪切模量接近贵金属Cu、Ag和Au。在所观察到的金属玻璃中，Pt/P玻璃表现出最高的ν= 0.42，而含Fe的玻璃倾向于具有较低的值。玻璃态合金中导电电子的行为与贵金属中导电电子的行为相似，这可能部分归因于过渡金属在Pt <$P、Pd <$P和Ni <$P合金中填充了d壳层轨道。金属玻璃的高v被认为是这些玻璃的韧性行为的原因。观察到金属玻璃的泊松比ν随温度降低而减小。结果表明，随着温度的降低，玻璃的体积分数降低，导致玻璃的断裂强度迅速提高。
The longitudinal and transverse sound velocities and Vickers hardness of metallic glasses (Pd1 −xNix)0.80P0.20, (Pd1 −xFex)0.80P0.20and (Pt1 −xNix)0.75P0.25have been measured. The elastic constants at room temperature exhibit a positive deviation with composition χ from linearity whereas the hardness shows a negative deviation. The increase in elastic constants has been attributed to a denser packing of the alloys on mixing. The reduced hardnessHrH/μversus χ exhibits a remarkable similarity to aTgversus χ relationship. This seems to indicate that flow mechanisms involved in metallic glasses above and below the glass-transition temperature are of similar origins. It is the excess entropy of disorder associated with alloying which lowers the hardness as well as the viscosity of metallic glasses. The metallic glasses possess in general a relatively high Poisson's ratioν≈ 0.40 and a shear modulus approaching that of the noble metals Cu, Ag and Au. Among the metallic glasses observed, the PtP glasses exhibit the highestν= 0.42, whereas the glasses containing Fe tend to have lower values. The phenomenon that the conduction electrons in the glassy alloys behave as in the noble metals may be partly attributed to the filling of d shell orbitals of the transition metals in the PtP, PdP and NiP alloys. The high ν of metallic glasses is believed to be responsible for the ductile behavior of these glasses. Poisson's ratio ν of metallic glasses was observed to decrease with decreasing temperature. It is suggested that the decreasing ν with falling temperature causes the rapid increase in the fracture strength of Fe-based glasses.