Damage mechanisms at room and high temperature in notched specimens of Al6061/Al2O3 particulate composites

Abstract

The aim of the present study was the investigation of the effects of macroscopic stress triaxiality on the presence and evolution of damage in particulate MMC. Two Al6061/Al 2 O 3 /10p and 20pparticulate reinforced composites were investigated on smooth and differently notched specimens pulled in tension at 20 and 250°C. Fractographic analyses and microstructural observations were carried out in order to identify and to map damage mechanisms. Particle fracture was the prominent form of material damage at 20°C, while debonding was the main damage mechanism at 250°C. The distribution of the two damage forms within the specimen volume was compared to the results of finite element analyses. At a given level of triaxiality (considered as the hydrostatic to Von Mises stress ratio), particle fracture localized in regions of high maximum principal stress, generally associated to the high hydrostatic stress. It was further observed that matrix/interface debonding concentrated in the same regions, developed on other particles at higher/lower load level depending on test temperature.

Influence of Notch on Mechanical Properties of Cf/Mg Composite Fabricated by LSEVI

“…To explain the matrix crack initiation process, Hillberry and Johnson (Ref 22) developed the strain-controlled matrix fatigue data and they modified the Smith-Watson-Topper effective strain parameter to predict cycles to fatigue damage initiation in the matrix material next to a notch. In addition to the above-mentioned studies, several researchers investigate the influence of notch on different kinds of MMCs (Ref [23][24][25]. However, considering the different features of matrix and reinforcement, we believe that the influence of notch on mechanical properties of C f /Mg composite needs to be further studied.…”

Structure and properties of nanocomposites prepared from ball milled 6061aluminium alloy with ZrO2 nanoparticles

“…Several recent studies have employed powder metallurgy (P/M) in the production of Al alloys due to the possibility of fabrication of the net-shaped parts at a low cost [1][2]. Many studies about fabrication of Al composite materials using ceramic particles have also progressed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The most recent research concerning Al composite materials has focused on improving their mechanical properties and the mechanism of sintering of a composite powder [2][3][4][5][6][7][8][9][10][11][12][13].…”

“…Many studies about fabrication of Al composite materials using ceramic particles have also progressed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The most recent research concerning Al composite materials has focused on improving their mechanical properties and the mechanism of sintering of a composite powder [2][3][4][5][6][7][8][9][10][11][12][13]. The most common used ceramic addition element is Al 2 O 3 powder [1][2][3][4][5][6][7][8][9][10][11][12][13] of the α allotropic form, however some authors use also ZrO 2 stabilized Y 2 O 3 powder addition [14].…”

“…The most recent research concerning Al composite materials has focused on improving their mechanical properties and the mechanism of sintering of a composite powder [2][3][4][5][6][7][8][9][10][11][12][13]. The most common used ceramic addition element is Al 2 O 3 powder [1][2][3][4][5][6][7][8][9][10][11][12][13] of the α allotropic form, however some authors use also ZrO 2 stabilized Y 2 O 3 powder addition [14]. There are variety of aluminum alloys used as a matrix for aluminum alloy-ceramic composites, such as 6XXX series [7][8][9][10][11][12][13][14][15], 2XXX [3,5,6], 7XXX [7], or technical purity aluminum [3,16].…”

“…The most common used ceramic addition element is Al 2 O 3 powder [1][2][3][4][5][6][7][8][9][10][11][12][13] of the α allotropic form, however some authors use also ZrO 2 stabilized Y 2 O 3 powder addition [14]. There are variety of aluminum alloys used as a matrix for aluminum alloy-ceramic composites, such as 6XXX series [7][8][9][10][11][12][13][14][15], 2XXX [3,5,6], 7XXX [7], or technical purity aluminum [3,16]. The ceramic phase was added to improve elevated temperature behavior [7,10], to improve the abrasive wear characteristics [4,5,14] or simply to obtain higher hardness [2][3][4][5][6][8][9][10][11].…”