Spark Plasma Sintering of AlN/Al Functionally Graded Materials.

Ziyang Xiu,Boyu Ju,Saiyue Liu,Gaohui Wu,Yiwei Song,Jindan Du,Wenshu Yang,Zhimin Li,Chang Zhou

doi:10.3390/ma14174893

Abstract

In this paper, six-layer AlN/Al gradient composites were prepared by a spark plasma sintering process to study the influences of sintering temperature and holding time on the microstructure and mechanical properties. The well-bonded interface enables the composite to exhibit excellent thermal and mechanical properties. The hardness and thermal expansion properties of the composite exhibit a gradient property. The hardness increased with the volume fraction of AlN while the CTE decreased as the volume fraction of AlN. The thermal expansion reaches the lowest value of 13–14 ppm/K, and the hardness reaches the maximum value of 1.25 GPa, when the target volume fraction of AlN is 45%. The simulation results show that this gradient material can effectively reduce the thermal stress caused by the mismatch of the thermal expansion coefficient as a transmitter and receiver (T/R) module. This paper attempts to provide experimental support for the preparation of gradient Al matrix composites.

Highlights

Graded materials are composites, for which the volume fraction of the reinforcement constituent changes, and the final composites exhibit gradually changing microstructure and properties [1,2,3,4]
Investigation on the functionally graded Al matrix composites with high reinforcement content variation prepared by SPS method has been rarely reported, as the optimized process parameters for each layer with different volume fractions would be different
The sintering temperature for six-layer AlN/Al gradient composites with AlN content varies from 0 to 45 vol.% has been optimized to be 600 ◦C, and dense gradient AlN/Al composite was obtained by one-step sintering using the optimized process

Summary

Introduction

Graded materials are composites, for which the volume fraction of the reinforcement constituent changes, and the final composites exhibit gradually changing microstructure and properties [1,2,3,4]. One effective way to control the CTE of aluminium is by adding low CTE ceramic phases, such as SiC [5,6] and AlN [7], into the Al matrix These functionally graded AlN/Al composites have been widely studied, as they can achieve the gradual distribution of the volume fraction and CTE. One side contains high volume fraction of AlN, and a low CTE was connected with the low thermal expansion of low temperature co-fired ceramic (LTCC) inside the T/R components. The other side, with lower volume fraction of the AlN/Al composite, is sealed with the T/R case (6061 Al) Introducing this gradient structure in the electrical packaging field Icnatnrobdeuecxipnegctthedistgorraeddiuencet tshtreugcitaunrtetihnertmhealelmecistrmicaatlchpasctrkeasgsianngdfieexldtencdansebreviecxepleifcete[d10t]o. Seidnitfefreirnegntevmolpuemraeftruarcetiaonnds ohfoAldliNngretinmfoeracreedtchoemtwpoosmiteossatriemqpuoirtetadnitffseirnetnetr.inSginptearrianmg etetemrsp.eHraitguhreerasnindtheroilndgitnegmtpimereataurreethcaentwporomviodset igmrepaotertradnrtisviinntgerfionrgcepsarfaomr tehtersd.eHnsiigfhiceartisointeorfinAglNte/mAlpecoramtuproecsaitnesp, raonvdidtheegirnecartearsderiinvihnogldfoinrcgetsimfoer ctahne rdeednuscifie ctahteionnumofbAerlNan/dAsl iczoemofpposoirtes,, wanhdichthies icnocnrdeausceivine thooilmdipnrgotviimnge cthaen mreedcuhcaentihcaelnaunmd btheerramnadl spirzoepoefrptioesreosf, cwohmicphosisitceosn[1d9u,2ci0v]e. to improInvitnhgisthsteumdye,cthhaeniincaflluaenndcetsheorfmsianlteprrionpgetretimespoerfactoumrepaonsidtehso[l1d9i,n2g0]t.ime on the microstrucItnurtehiosfstAuldNy/,Athl ecoinmflpuoesnitceess wofesreintinerviensgtigteamtepde. rTathueresiaxn-ldayheorelddinggratdimieentonmtahtermialiscwroesrterusuctcucreessoffuAllylNs/inAtel rceodmupsoisnigtesthweeSrPe Sinpvreosctiegsast.eTdh. eThmeiscirxo-sltaryuecrteudregraanddietnhtemrmataelraianlds wmeercehsaunciccaelsspfruolplyerstiinesteorfedthuesginragdtihenetScPoSmpprooscietesss.wTehree cmhaicrraocstterruizcetudr. e and thermal and mechanical properties of the gradient composites were characterized

Materials and Methods

Findings

Conclusions