Chip Formation during Precision Cutting of Metallic Glass

2016 ◽  
Vol 1136 ◽  
pp. 265-270
Author(s):  
Hiroyuki Kodama ◽  
Koichi Okuda ◽  
Tsukasa Inada
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Shear Angle ◽  
Chip Formation Mechanism

The chip formation mechanism during precision cutting of metallic glass (Zr55Cu30Ni5Al10 at%) was investigated around the glass transition temperature (673 K). Orthogonal cutting of metallic glass are conducted on a fly-cutting machine at various cutting speeds. The new surface of the chips was slightly shiny while the free surface exhibited lamellar slip structure. The cutting temperature was a proportional to the cutting ratio and chip shear angle. The surface integrity worsened with an increased flow of cutting chip due to an increase in the cutting speed. An increase in the cutting temperature caused the chips formation to change from flow type chips to discontinuous chips. When the cutting speed exceeded 300 m/min, the shear angle increased while the shear pitch of the chips decreased. It appears that when the cutting temperature exceeded the glass transition temperature, the strength of the metallic glass decreased and the ductility mode changed due to viscous flow.

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

Structural relaxation and nanomechanical behaviors of La65Al14Ni5Co5Cu9.2Ag1.8 bulk metallic glass (BMG) with a low glass transition temperature during annealing have been investigated by calorimetry and nanoindentation measurement. The enthalpy release of this metallic glass is deduced by annealing near glass transition. When annealed below glass transition temperature for 5 min, the recovered enthalpy increases with annealing temperature and reaches the maximum value at 403 K. After annealed in supercooled liquid region, the recovered enthalpy obviously decreases. For a given annealing at 393 K, the relaxation behaviors of La-based BMG can be well described by the Kohlrausch-Williams-Watts (KWW) function. The hardness, Young’s modulus, and serrated flow are sensitive to structural relaxation of this metallic glass, which can be well explained by the theory of solid-like region and liquid-like region. The decrease of ductility and the enhancement of homogeneity can be ascribed to the transformation from liquid-like region into solid-like region and the reduction of the shear transition zone (STZ).

scholarly journals Effect of Cutting Temperature on Bending Properties of Carbon Fibre Reinforced Plastics

2019 ◽  
Vol 26 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Ben Wang ◽  
Bowen Yang ◽  
Minghai Wang ◽  
Yaohui Zheng ◽  
Xianjun Hong ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Carbon Fibre ◽  
Cutting Temperature ◽  
Bending Stress ◽  
Bending Properties ◽  
Reinforced Plastics ◽  
Increasing Temperature ◽  
Carbon Fibre Reinforced Plastics

AbstractHigh cutting temperatures are easily generated during the machining of carbon fibre reinforced plastics (CFRP) and can induce serious damage during machining such as delamination. The purpose of this paper is to study the influence of cutting temperature on the performance of CFRP after machining. CFRP specimens were heated to temperatures within the vicinity of cutting temperatures generated during machining, then air-cooled and their bending properties investigated. The results showed that temperature had significant influence on the bending stress of CFRP. With increasing temperature, bending stress decreased and was lowest when the temperature was close to the glass-transition temperature. It was concluded that the bending properties of CFRP could be seriously affected if the material temperature was close to the glass-transition temperature and maintained for a period. As a result, cutting temperature should be kept lower than the glass transition temperature during machining.

Fractional Exponent of the Modified Stokes-Einstein Relation in the Metallic Glass-Forming Melt Pd43Cu27Ni10P20

2010 ◽  
Vol 146-147 ◽  
pp. 1463-1468
Author(s):  
Masahiro Ikeda ◽  
Masaru Aniya
Keyword(s):  
Diffusion Coefficient ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bond Strength ◽  
Coordination Number ◽  
Einstein Relation ◽  
Glass Forming ◽  
Highly Correlated

The diffusion coefficient in the metallic glass-forming systems such as Pd-Cu-Ni-P exhibits a marked deviation from the Stokes-Einstein (SE) relation in the proximity of the glass transition temperature. Such a deviation is characterized by the fractional exponent p of the modified SE expression. For the material Pd43Cu27Ni10P20, it has been reported that it takes the value p = 0.75. In this work, it is shown that the value of p is highly correlated with the ratio ED / ENB, where ED and ENB are the activation energies for diffusion coefficient D and cooperativity NB defined by the Bond Strength-Coordination Number Fluctuation (BSCNF) model. The present paper reports that for the metallic glass-forming melt Pd43Cu27Ni10P20, the fractional exponent p can be calculated accurately within the framework of the BSCNF model.

An Experimental Study for Crystallization Characteristics of Nd-Based Alloy

2011 ◽  
Vol 268-270 ◽  
pp. 611-615
Author(s):  
Feng Yang ◽  
Zhi Hua Gao ◽  
Di Wang ◽  
Yang Liu
Keyword(s):  
Experimental Study ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Heating Temperature ◽  
Liquid Region ◽  
Magnetic Alloys ◽  
Ordinary Temperature ◽  
Transition Temperature Increase

The bulk metallic glass has received much attention from scientist and engineer. In this paper, we fabricated metallic glass of Nd-based and carried out experimental research. This kind of metallic glass has shown a distinct glass transition and stable super-cooled liquid region. At the same time, we find the paramagnetic performance of Nd-based metallic glass is different from other hard magnetic alloys at ordinary temperature. The DSC experiment indicate that the glass transition temperature increase with the heating temperature.

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