STUDY OF MILLING DURATION (1, 3, 5, AND 8 HOURS) INFLUENCE ON Ti-5Cu SINTER ALLOY PORE, MICROSTRUCTURE, AND HARDNESS AS A PRODUCT OF HOT AND COLD COMPACTION

• Main Author: Airy Utomo, Oei
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/39133
• Institution: Institut Teknologi Bandung

Titanium as an implant alloy has good biocompatibility, corrosion resistance, and low modulus of elasticity. Adding of copper into the alloy will give antibacterial ability also increase strength and hardness. Powder metallurgy as one of the methods to produce an implant always produces a porous product. Those pores will decrease mechanical properties and become a stress concentrator. Combining compaction and sintering in one step at a high temperature can produce pores as few as possible. However, that method needs high cost and high-temperature resistance dies material. To overcome the problem mentioned, doing hot compaction and sintering separately, in two stages will be an alternative. Moreover, reducing pores can be done by increasing mechanical alloying or milling duration. Milling duration affects powder size, morphology, and properties, which will affect product porosity. In this research Ti-Cu sinter alloy with 5wt% of copper was used. Titanium and copper powder were milled using Planetary Ball-mill with duration 1, 3, 5, and 8 hours. The milled powder's microstructure was observed using Scanning Electron Microscope (SEM) and powder size is analyzed using Powder Size Analyzer (PSA). Then the powder was compacted, using hot (500ºC) and cold compaction method with compaction pressure 100 bar, followed by 2 hours of sintering at 950oC. The compacted sample's microstructure was observed its pore using an optikal microscope. Meanwhile, the hot compacted sample and sintered sample were observed using an optikal microscope and SEM for microstructure observation, Energy Dispersive Spectrometer (EDS) and X-Ray Mapping test to get elements composition, and hardness test using Vickers Hardness Tester. The results show that the powder change in shape and size as the milling duration increase. All of the sintered specimens, except specimen produced via cold compaction with milling duration 8 hours also hot compaction with milling duration 5 and 8 hours, have ?-Ti phase and lamellar structure (?-Ti and Ti2Cu). Meanwhile, the other 3 specimens show the appearance of intermetallic phase Ti2Cu not in a lamellar structure form. In general, increasing milling duration and hot compaction followed by sintering method decrease porosity area, pore size, and grain size, also increase alloy hardness, which is owned by sintered alloy produced by hot compaction with 8 hours milling. The smallest porosity area, pore size, and grain size, also highest hardness respectively are 1,19%; 11,02 µm; 17,39 µm, dan 555,87 HV.