The influence of particle size distribution on the properties of metal-injection-moulded 17-4 PH stainless steel

Metal injection moulding (MIM) is a near-net-shaping powder metallurgy technique suitable for the cost-effective mass production of small and complex components. In this paper, the effects of the metal powder particle size on the final properties of 17-4 PH stainless steel are reported. Three different particle sizes (d50 33.0, 7.91 and 4.04 μm) were used to prepare the injectable MIM feedstocks using a CSIR-developed wax-based binder system at a fixed solids loading of 60 vol.%. The distribution slope parameter and the rheological flow index behaviour were used to predict the flowability of the feedstocks. The effects of the particle size on MIM products were established. The results are discussed in terms of the subsequent microstructural and mechanical properties of MIM 17-4 PH stainless steel against the established MPIF Standard 35.The DST and the CSIR.http://www.saimm.co.za/journal-papersam2016Materials Science and Metallurgical Engineerin

Development of a biocompatible Ti-Nb alloy for orthopaedic applications

Metallic biomedical implants such as titanium-based alloys are very useful for orthopaedic applications due to their excellent properties which responds to changes in temperature and other conditions. However, biological toxicity due to alloying elements and relatively high Young’s modulus or mechanical incompatibilities of previously used Ti alloys have necessitated the development of biocompatible alloys with compatible mechanical properties such as beta-titanium alloys. This study aims at production of beta-titanium alloy with enhanced properties by varying milling speeds. Ti and Nb powders were mechanically alloyed using the high energy ball-mill Zoz-Simoloyer® to produce Ti-7Nb alloys by varying the milling speed. The milling process produced irregular shaped powders with increasing particles sizes as the milling speed increased due to fragmentation and cold welding during agglomeration. The mechanical alloying process had good yield. The predominant phases of the inhomogeneously milled alloy were alpha and beta phases.Authors acknowledge the financial support of the department of Science and Technology (DST) South Africa. The technical support of the Council of Scientific and Industrial Research (CSIR) and the contribution of the University of Pretoria is acknowledged as well.The Department of Science and Technology (DST) South Africa.http://iopscience.iop.org/journal/1757-899Xam2020Materials Science and Metallurgical Engineerin