Microstructure and Properties of Cu-Cr-Zr Alloy after Rapidly Solidified Aging and Solid Solution Aging

The structure and properties of Cu-Cr-Zr alloy were studied after rapidly solidified aging and solid solution aging.At the early stage of aging （500℃ for 15 rain）, the hardness and the conductivity of the alloy rapidly solidified are 143 HV and 72% IACS, respectively. Under the same aging condition, the hardness and electrical conductivity of the alloy solid solution treated can reach 86 HV and 47% IACS, respectively. The microstructure was analyzed, and the grain size after rapid solidification is much smaller than that after solid solution treatment. By rapidly solidified aging the fine precipitates distribute inside the grains and along the grain boundary, while by solid solution aging there are large Cr particles along the grain boundary.

CALCULATION OF THE DAMPING OF THE Zn-27Al ALLOY BASED ON THE MICRO INTERFACE SLIDING MODEL

The microstructures of the Zn-27Al alloy after modification, solid-solution treatment, and natural aging were studied. It was clarified why the damping properties of Zn-27Al alloys, after treatment, had advanced most on the basis of analyzing the microstructures. Approximate expressions have been educed, which can be used to quantificationally work out the damping of the Zn-27Al alloy on the basis of the micro interface sliding model. By comparing the testing damping properties of the foundry Zn-27Al alloys and the Zn-27Al alloys after modification, solid solution, and natural aging, it was shown that the expressions were rational.

Crystals based on solid solution of Ag_(1-x) Tl_xBr_(1-x) I_x for the manufacturing of IR fibers

For the development of fiber optics for the range from 0.2 to 50.0 μm, one needs light-stable, nonhygroscopic, ductile crystals that would be transparent within this spectral range and have a lack of cleavage, and from which the flexible infrared （IR） fibers are extruded. The crystals based on solid solutions of silver and monadic thallium haides meet the conditions listed above. Consequently, by differential thermal and x ray analyses, we study the TIBr-TII phase diagram using the crystals with optimal compositions, which we grow ourselves. We also manu- facture light-stable nanocrystalline IR fibers that are transparent at longer wavelengths compared with AgC1-AgBr fibers.

Strength Improvement in ZK60 Magnesium Alloy Induced by Pre-deformation and Heat Treatment

The influence of pre-deformation and heat treatment on mechanicalproperties of as-extruded ZK60 alloy was investigated.The experimentalresults indicated that the solid solution,pre-cold rolling and artificialaging treatments remarkably improved the mechanicalstrength of alloys compared with the asextruded condition.Especially,pre-cold rolling in 5% reduction combined with artificialaging at 150 ℃ for 20 h was determined as the optimum heat treatment condition,which resulted in a yield strength of 333 MPa with an increment of 87 MPa and ultimate tensile strength of 373 MPa.High density of nanoscale precipitates in α-Mg matrix observed in this sample was beneficialto enhancing the strength.The as-extruded sample showed a typicalbrittle fracture while the solution treated sample exhibited ductile-fragile failure characterized by cleavage fractures,river patterns,and tear ridges.And the sample after pre-cold rolling combined with aging presented more equiaxialdimples with a great amount of cracked particles in them.The above-mentioned observations were analyzed in terms of microstructure and possible strengthening mechanism in the extruded ZK60 alloy.

Microstructure and property of laser additive manufactured alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si after aged at different temperatures

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar microstructures.In this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was investigated.The results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' matrix.Aging at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine microstructure.By increasing the aging temperature,the number of α_(s) decreases but with coarsened microstructures.When aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°C.The changing size of α_(s) obviously influences the property of the alloy.The fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.