PENGARUH PENAMBAHAN MANGAN TERHADAP SIFAT MAMPU TEMPA PADUAN Co-35Cr-5Mo UNTUK APLIKASI IMPLAN

Abstract

THE EFFECT OF Mn ADDITION ON FORGING ABILITY OF Co-35Cr-5Mo ALLOY FOR IMPLANT APPLICATIONS. The applications of Co-Cr-Mo alloys are widely used as an implant material such as knee and hip joint. Subject of this research relates to the forge ability of Co-35Cr-5Mo without and with various addition of Mn approximately 0.2-0.4-0.6-0.8-1 (weight %). Co-35Cr-5Mo-xMn (0-20 weight %) phase diagram is calculated using data base in the Thermo-Calc software. Co-35Cr-5Mo-xMn (0-1 weight %) alloy ingots are obtained through melting and solidifying process by using tri arc melting in vacuum condition at temperature above 1400 ºC. Homogenizing is carried out using vacuum furnace with high purity argon gas at temperature 1200 ºC for 24 h. After forging process at T = 1250 ºC, Co-35Cr-5Mo-0.4Mn alloy ingot did not obtain any significant cracking when compared to others. XRD results reveal that ε phase and σ phase consist in all Co-35Cr-5Mo-xMn (x=0-1 weight %) alloys. Metallography examinations show precipitations of σ phase along austenite grain boundaries and striations in the interior of austenite grains. Striations are to be expected as ε phase or deformation twinning. From this research study concludes that Co-35Cr-5Mo-0.4Mn is suitable for forging process. The existence of striation and σ phase lead to the low grade of forging ability in these alloys.