International Survey

Plasma spray process produces stronger titanium parts

The arc plasma spray (APS) process is known to produce a rapidly solid- ified, micro.fine grained structure. With proper controls, a dense, rapid- ly solidified structure with low oxy- gen content can be produced, which can be manipulated further with post-spray heat treatment. Coatings and near-net shapes can be fabricat. ed by the APS process. While it can be applied to many materials, one of the more interesting candidates is

titanium and its alloys. An alloy such as Ti6AI4V forms a martensitic alpha-prime microstructure when rapidly solidified. Through a combi- nation of solution treating and age- ing, this structure will decompose to a f ine.grained alpha-plus-beta structure.

When this process is applied to a plasma.sprayed Ti6AI4V deposit, the resulting microstructure has no splat lines micro-fine grains and no

damage from exceeding the beta transition temperature. Therefore the plasma spray process can be used to produce near-net shapes of titanium alloys which have superior properties over similar components formed by conventional casting or powder metallurgy.

Further information: APS- Materials. Tel: +1 (513) 278-6547

Self.piercing fastener joins two meta ls together

The AKH Fas.ner System is designed to join two or more pieces of material (usually steel or alumin- ium) with a combined material thick- ness of 0.075in to 0.36in (2-9mm). The press forces the fastener into the material layers to be joined. The fastener pierces the materials to be joined (fig 13a), whilst, as in a com- mon punch and die operation, the lower die shears the punched material and allows the slug to drop out (Fig 13a). The FAS-NER is the same length as the total thickness of the materials being joined, so takes the place of the pierced section (Fig 13c). Coining rings on the system's dies then cause material to flow into and around the concave fastener. After the coining operation, the ends of the fastener are virtually flush with the outer surfaces of the stacked materials (Fig 13d). Total press cy- cle times are up to 60/rain.

FAS.NERs are inserted through a complete line of presses. These may be floor, bench or overhead- mounted, either hydraulic or air tog- gle. Vibratory or magazine feed sys- tems can be used with the presses.

Further information: AKH Fas- ner System: 3980 Albany Street, Mchenry, Illinois, USA IL 60050. Tel: +1 (815) 344-3130.

Fastener punches hole in thin materials, then coining rings on dies force materials to flow into and against concave fastener.

106 MATERIALS & DESIGN Vol. 11 No. 2 APRIL 1990