Hardness comparison between Co – Cr metal alloy specimens made by different methods

Abstract

The aim of this study is to compare the hardness of Co–Cr metal alloy specimens made by different methods and how it is influenced by multiple temperature changes. Fifty-four samples are made by three different methods and are accordingly divided in three groups – group M (Milling), group LP (Laser Printing) and group LW (Lost Wax), with 18 samples each. All of them contain three subgroups with six samples – metal samples with no thermal cycles (subgroup 1), metal samples with one thermal cycle (subgroup 2) and metal samples with two thermal cycles (subgroup 3). Their Vickers hardness is evaluated by a weight of 1 kg applied for 20 s. The results are presented in tables. The average hardness is the highest for group LP – 509, followed by group M – 440, and for group LW it is 401. For the subgroups, the best results are exhibited by the samples of subgroup 2 – 430, followed by subgroup 3 – 457, and subgroup 1 – 450.