Comparative Study on Cold Compaction Behavior of TiH2 Powder and HDH-Ti Powder

The compaction mechanism of titanium hydride powder is an important issue because it has a direct impact on density and strength of green compacts and ultimately on the physical and mechanical properties of a final sintered products. In this paper, the characteristics and compaction behavior of titanium hydride and hydrogenation-dehydrogenation titanium powders are comparatively studied and analyzed for better understanding of compaction mechanism of brittle low-strength titanium hydride. The results indicate that the particles of titanium hydride powder are easily crushed under compaction loading at relatively low pressure well below compression strength of bulk titanium hydride, the degree of particle crushed increases with the increase of pressure. The compaction behavior of titanium hydride powder mainly includes the rearrangement and crushing of particles in the early compaction stage, minor plastic deformation, if any, and further rearrangement of particle fragments with filling the pores in the later stage. Such compaction behavior provides relative density of green hydride compacts higher than that for titanium powder of the same size. The relatively coarse titanium hydride powder with wide particle size distribution is easier to fill the pores providing highest green density.

Polylactide and its Composites on Various Scales of Hardness

Polylactide (PLA) has become a widely applied material. Its hardness property has, however, not been a subject of intense study. This study attempts to examine the hardness values of Polylactide and its composites on ten hardness scales. Polylactide composites were developed using three reinforcements (i.e., chitosan, chitin, and titanium powders). The compositing method was the melt-blending technique. Vickers microindentation test was carried out on all the developed samples. The experimental values obtained were related to nine (9) other scales of hardness via an online reference interface. Results showed that the Brinell and Rockwell hardness scales agreed, to a large extent, with the experimental values from several studies. Hence, this work can serve as a reference material on the Brinell and Rockwell hardness values of the unreinforced and reinforced composites considered in this study. The developed materials were also represented on the Mohs scale of hardness with unreinforced PLA having the least value of hardness which corresponds to the value of gypsum on the Mohs scale while the PLA reinforced with 8.33 weight (wt.) % of titanium powder has the highest value of hardness corresponding to the value of a material in-between calcite and fluorite. The hardness values obtained on Shore scleroscope could not agree with the experimental values from various studies. Succinctly, the three particulate fillers increased the hardness properties of PLA. The results of this study would go a long way in helping industrialists and researchers in the correct applications of PLA and its composites.

Polylactide and its Composites on Various Scales of Hardness

Polylactide (PLA) has become a widely applied material. Its hardness property has, however, not been a subject of intense study. This study attempts to examine the hardness values of Polylactide and its composites on ten hardness scales. Polylactide composites were developed using three reinforcements (i.e., chitosan, chitin, and titanium powders). The compositing method was the melt-blending technique. Vickers microindentation test was carried out on all the developed samples. The experimental values obtained were related to nine (9) other scales of hardness via an online reference interface. Results showed that the Brinell and Rockwell hardness scales agreed, to a large extent, with the experimental values from several studies. Hence, this work can serve as a reference material on the Brinell and Rockwell hardness values of the unreinforced and reinforced composites considered in this study. The developed materials were also represented on the Mohs scale of hardness with unreinforced PLA having the least value of hardness which corresponds to the value of gypsum on the Mohs scale while the PLA reinforced with 8.33 weight (wt.) % of titanium powder has the highest value of hardness corresponding to the value of a material in-between calcite and fluorite. The hardness values obtained on Shore scleroscope could not agree with the experimental values from various studies. Succinctly, the three particulate fillers increased the hardness properties of PLA. The results of this study would go a long way in helping industrialists and researchers in the correct applications of PLA and its composites.

The Effect of Ball Size on Hardness of Mechanically Alloyed Al-10wt.%Ti Powders

Particle size and hardness of Al-10%wt.Ti powders due to the influence of ball diameter have been carried out using mechanical alloying techniques. The milling device used consisted of a Fritsch Pulverisette-5 planetary type ball mill with the rotational speed of about 360 rpm and balls size of 10, 15 and 20 mm. The materials used are stearic acid which was used as a process control agent, aluminum and titanium powders. A mixture of aluminum and titanium powders has the composition of Al-10wt.%Ti. The Al-10wt.%Ti powders, stearic acid and stainless-steel balls were added to the Fritsch Pulverisette-5 planetary in the argon gas environment. The weight ratio of stainless steel balls to the Al-10wt.%Ti powder was 20 : 1. The mixing time process was carried out for 5, 10, 15, 20 and 30 hours, respectively. Changes in phase compositions of these Al-Ti powders under different ball mill sizes were examined by XRD, and the optimum experimental parameter was obtained: the ball mill size was 20 mm. It was found that from the diffraction patterns of the Al-10wt.%Ti powders, the peaks of titanium begin to disappear with the increasing of the milling time, which indicates the increasing degrees of alloying of titanium atoms in the aluminum matrix. The microhardness test results showed that the hardness increases with increasing ball size.

Recycling of Titanium Alloy Powders and Swarf through Continuous Extrusion (ConformTM) into Affordable Wire for Additive Manufacturing

Over the last 20 years, there has been growing research and development investment to exploit the benefits of wire deposition additive manufacturing (AM) for the production of near-net shape components in aircraft and space applications. The wire feedstock for these processes is a significant part of the overall process costs, especially for high-value materials such as alloyed titanium. Powders for powder-based AM have tight specifications regarding size and morphology, resulting in a significant amount of waste during the powder production. In the aerospace sector, up to 95% of forged billet can be machined away, and with increasing aircraft orders, stockpiles of such machining swarf are increasing. In this study, the continuous extrusion process—ConformTM—was employed to consolidate waste titanium alloy feedstocks in the forms of gas atomised powder and machining swarf into wire. Samples of wire were further cold-drawn down to 40% reduction, using conventional wiredrawing equipment. As close to 100% of the waste powder can be converted to wire by using the ConformTM process. This technology offers an attractive addition to the circular economy for manufacturers and, with further development, could be an important addition as industries move toward more sustainable supply chains.