Abstract
The aim of this study is to fabricate a Cu-0.5wt%TiB2 composite by mechanical alloying (MA) and spark plasma sintering (SPS). Increasing the milling time, the powders are subjected firstly to a severe flattening process and then to intense welding, which promotes the refinement of TiB2 particles, their uniform dispersion in the metal matrix, and the adhesion between the two constituents. Sintered metal matrix composites (MMC) exhibit density values between 99 and 96%, which are generally decreased by increasing milling time in view of the stronger strain hardening. On the other side, the hardness increases with milling time due to the refinement of TiB2 particles and their improved distribution. The hardness of MMC is three times higher (225 HV0.05) than the starting hardness of atomized copper (90 HV0.05). Tensile tests show a loss of ductility, but ultimate tensile strength has been increased from 276 MPa of atomized copper to 489 MPa of MMC milled for 240 min. The thermal conductivity of MMC is comparable to that of atomized copper (300 W/mK), i.e., much higher than that of the commercial Cu-Be alloy (Uddeholm Moldmax HH, 106 W/mK) typically used for tooling applications.
Highlights
The need to improve the properties and performance of components working under severe service conditions has always been the driving force toward new and advanced materials
The microstructure and some important properties of Cu‐0.5 wt% TiB2 composite fabricated by mechanical alloying and Spark Plasma Sintering in the solid state were investigated
The microstructure and some important properties of Cu-0.5 wt% TiB2 composite fabricated by mechanical alloying and Spark Plasma Sintering in the solid state were investigated
Summary
The need to improve the properties and performance of components working under severe service conditions has always been the driving force toward new and advanced materials. The world of tooling is demanding materials combining high wear resistance and thermal conductivity [1]. Copper, characterized by an intrinsic high electrical and thermal conductivity, is a suitable candidate for new and challenging applications as high-performance materials in thermal and electric fields. Copper shows a low hardness and poor resistance to wear and fatigue. For many applications, it is important to improve the copper properties to match these requirements. An effective method is the production of copper-matrix composite materials reinforced by the dispersion of a hard second phase [2,3]
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