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Rigid perpetual joining of materials is one of the main demands in most of the manufacturing and assembling industries. AISI D2 cold work tool steels is commonly known as non-weldable metal that a high quality joint of this kind of material can be hardly achieved and almost impossible by conventional welding. In this study, a novel thixowelding technology was proposed for joining of AISI D2 tool steel. The effect of joining temperature, holding time and post-weld heat treatment on microstructural features and mechanical properties were also investigated. Acceptable joints without defect were achieved through the welding temperature of 1300 • C, while the welding at lower temperature resulted in a series of cracks across the entire joint that led to spontaneous fracture after joining. Tensile test results showed that maximum joint tensile strength of 271 MPa was achieved at 1300 • C and 10 min holding time, which was 35% of that of D2 base metal. Meanwhile, tensile strength of the joined parts after heat treatment showed a significant improvement over the non-heat treated condition with 560 MPa, i.e., about 70% of that of the strength value of the D2 base metal. This improvement in the tensile strength attributed to the dissolution of some amounts of eutectic chromium carbides and changes in the microstructure of the matrix. The joints are fractured at the diffusion zone, and the fracture exhibits a typical brittle characteristic. The present study successfully confirmed that by avoiding dendritic microstructure, as often resulted from the fusion welding, high joining quality components obtained in the semi-solid state. These results can be obtained without complex or additional apparatuses that are used in traditional joining process.

A patient’s portable bed defined as a very special designed bed used for patients denotes the “special design” of such a device which has typical features meeting the needs of a bedridden patient. It is also defined as an advanced device or mechanism used to carry and transfer a patient’s body which is typically developed to meet the patient’s physical demands such as mobility or movement. A new method in a rehabilitation bed for transporting a bedridden patient is developed and applied to avoid staying at hospital with costly medical treatment and such obstacles, therefore to conquer these problems, the proposed design of the bed is formulated based on literature survey as well as consult the medical staff. This paper discusses the specification ,mechanism design and evaluating healthcare activities for development of a new style of active bed that provides high mobility with comfortable sleeping for bedridden persons and it also can meet the demands of those who may be required to take hospital beds to use at home particularly in a case of nursing disabled persons.

In many circumstances, a high quality joint of dissimilar metals can be hardly achieved by conventional welding process. In this study, a new process of joining semi-solid AISI D2 tool steel and AISI 304 stainless steel using a partial remelting method is proposed. The differences of two dissimilar steels at the test temperature on microstructural developments across the interface joint area were investigated. After Thixo-Joining, Interfacial microstructures were examined by optical microscope and scanning electron microscope (SEM) equipped with EDS (energy dispersive spectroscopy) in order to verify the interface welded area during the joining process while X-ray phase analysis was performed to identify the phase evolution and the type of carbides. The experimental results showed that at 1300°C a full penetration welded joint can also be clearly seen, whereby the base metal (D2 tool steel) is connected to the insert metal (304 stainless steel) along the bonding boundary to achieve what appears to be a perfect joining at the interfaces of both metals.

Earlier work has shown that Al-5.7Si-2Cu-0.3Mg aluminium alloy is suitable for thixoforming process. Here, the dry sliding wear behaviour of the alloy, in the as-cast and thixoformed conditions were investigated. The cooling slope technique was used to produce the alloy with globular microstructure for the thixoforming process. Both the thixoformed and cast samples were subjected to T6 heat treatments prior to the wear tests. The tests were carried out using a pin-on-disc tribometer, against a hardened M2 tool steel disc of 62 HRC at different loads, under dry sliding conditions at fixed sliding speed and sliding distance of 1 m.s–1 and 5 km respectively. The microstructural response, worn surfaces were thoroughly and carefully examined using various methods such as scanning electron microscopy, energy dispersive spectroscopy, and differential scanning calorimetry. The density of the heat treated thixoformed alloys showed significant increase in the hardness property, among others, due to its reduced porosity. Their wear test results also observed that the weight loss of materials increase with an increase in the input load and the sliding distance for all samples. However, the as-cast alloy displayed higher wear rate compared with the thixoformed alloys. In general, the wear mechanisms showed a mixture of abrasive, oxidative and delamination wear (mild wear) at low applied loads and mainly an adhesive (severe wear) at high applied loads.